Novak Djokovic, the No. 1-ranked men’s player in the world, has a chance to make history: complete the calendar-year Grand Slam and break a tie with Roger Federer and Rafael Nadal, who also have 20 major titles, for the most in men’s tennis history.

Daniil Medvedev can spoil Djokovic’s bid to become the first man to win all four majors — the Australian Open, French Open, Wimbledon and US Open — in the same year.

Who comes out on top in Sunday’s US Open men’s final? Our experts break down the magnitude of Djokovic’s run, what makes him so good at 34 years old and what the 25-year-old Medvedev needs to do to pull off the upset.

Djokovic is looking at history and has wavered at times in the tournament, especially in first sets. What weaknesses/areas of opportunity might exist that Medvedev could take advantage of?

Brad Gilbert: Yellow card for stupidity of question. He’s never wavered, and there are no weaknesses in his game than his overhead. That’s a yellow-card question for even saying that he wavered. It’s best-of-five for a reason, and he is great at navigating that. There’s nothing that Medvedev can take advantage of, but it is key for him, if he has any chance, to win the first set and serve tremendous.

Bill Connelly: His return abandoned him against Alexander Zverev in the semis, but Djokovic’s biggest issue has been obvious: He has taken some haymakers out of the gate. He has dropped six sets in this tournament, and he has dropped the first set in four straight matches. He was too dominant from the second set on against Kei Nishikori, Jenson Brooksby and Matteo Berrettini, but dropping the first set to Zverev could have cost him dearly had he not eked out a massive, tight third set. Medvedev is more than good enough to take two of the final four sets if he cashes in on the first.

Alexandra Stevenson: First. I think Djokovic wavers in first sets because he’s measuring his opponent — the hit of the ball, the rhythm of the court. Surely, losing a first set can be considered an opportunity for Medvedev. Look for Djokovic’s serve motion. Does he look strong? When he’s driven back, sometimes he doesn’t move through the forehand and he gets caught with his hit in the net.

The weakness for Medvedev to attack? Go at Djokovic’s all-court consistency. Every pattern. Every ball. Break him down. Can Medvedev get Djokovic thinking about his forehand? Djokovic has shown that his opponents wear down in terms of their physical prowess on court. Like Zverev.

Rennae Stubbs: That Djokovic is not invincible. I think Medvedev would have taken some confidence in knowing Djokovic has shown vulnerability throughout, but he also understands no one is as good as Djokovic over five sets. His focus will be squarely on not letting up if he gets a lead.

Aishwarya Kumar: During the semifinals Zverev tested Djokovic, running him all over the court, particularly in the third and the fourth sets. The match saw some of the longest rallies of the tournament, and Djokovic, who never looks tired, showed signs of slight weariness. If Medvedev is able to move him around the court and challenge him to keep his serve — and consistently at that — he might be able to take a set and put some pressure on the world No. 1.

Ohm Youngmisuk: Djokovic raised his level of play when he had to, especially in the fifth set against Zverev. But he has given his opponents opportunities. No one has been able to take advantage yet. Medvedev has to take this from Djokovic. He’ll have to do more than just get everything back against Djokovic. He will have to be the aggressor. And he also has to hope that the pressure of trying to make history will also wear on Djokovic too.

D’Arcy Maine: It has to start with taking advantage of Djokovic’s recent trend of slow starts and stealing the first set. Beyond that, Djokovic has certainly proved difficult, if not impossible, to beat. However, Medvedev has their clash at the 2020 ATP Finals to look to for guidance as well. In that match, he defeated the world No. 1 with a staggering defensive display and strong serving, essentially beating Djokovic at his own game. The stakes are much higher this time around, and it’s a best-of-five match, but on that day Medvedev had an answer for everything Djokovic tried. Trying to replicate that game plan might be his best hope.

Medvedev has almost quietly made the final. What has been the key to his success?

Gilbert: He has been serving great all tournament and has dropped only one set. A fast start will also be key for Medvedev.

Connelly: He has been serving like crazy. The serve has improved overall this year, and his numbers in these later rounds have been wild. Medvedev has won at least 80% of his first-serve points in five of six matches — to put that in perspective, John Isner is only at 79% for the year, Reilly Opelka 77% — and over the last three rounds he’s landed an especially high percentage of his first serves in. Obviously those numbers will get the stiffest possible test against Djokovic: Medvedev won only 69% of his first-serve points in their Australian Open final meeting, but combined with his increasing willingness to come to the net, Medvedev’s service game overall has improved significantly since Melbourne.

Stevenson: His movement. People can criticize where Medvedev stands — way in the back of the court — but look at where he ends up. His coverage of the court has brought him to the final. He’s going to be a player trying to bust open a no-hitter ball game, only this time, it’s the calendar-year Grand Slam.

Stubbs: Believing in himself and his ability to play on hard court. Because his game transfers so well to this surface, I think he now believes he belongs in the final.

Kumar: While all eyes were on Djokovic, and then the teens making history at the US Open, Medvedev has dominated his end of the draw, dropping just one set in the entire tournament on his way to the final. The key to his success: his serve. He has a stellar first and second serve, and he rarely gets broken. He also gets to every ball, which leaves a lot of his opponents scrambling to pick up the pieces. This, combined with his ability to keep his level up throughout a match, has given him the quiet confidence and the edge to get to his second US Open final and his second Grand Slam final of the year.

Youngmisuk: Medvedev is like a robot. He just grinds and grinds and is like a ball machine. His consistency is a weapon. But he has also had a relatively easy path here, facing just two double-digit seeds on his way to the final. He’ll need fresh legs against Djokovic.

Maine: Considering how much attention Medvedev received during his 2019 run to the final, it’s almost shocking to see how under the radar he is this time around. But make no mistake — that’s by design. He said on Friday he was happy to have had such a “smooth” tournament thus far. He has dropped just one set thus far, and by getting the job done efficiently each match, and with no fireworks or fan interactions, he has been able to simply focus on playing his incredible tennis.

Perhaps nothing better exemplifies his locked-in demeanor than the second set of his match against Felix Auger-Aliassime. Down 5-2 in the second set, and facing two set points at 5-4, Medvedev used his experience to build a remarkable comeback to take the set, 7-5, and win the match in straight sets.

What is the blueprint Djokovic should follow to beat Medvedev?

Gilbert: There is no blueprint. When people ask these questions — every player plays differently. Djokovic is 2-0 head-to-head in best-of-five, and they’re 3-3 in every other match. So, the fact that it’s a best-of-five is a huge advantage to Djokovic.

Connelly: The body-blow blueprint is the best card Djokovic still has to play. His biggest remaining advantage over the rising crop in men’s tennis is his pure best-of-five endurance. It saved him against Tsitsipas in the French Open final, and it saved him against Zverev on Friday night. Medvedev’s hard-court game is as good or better than Djokovic’s at this point — he has won a higher percentage of both service and return points than Djokovic on hard courts over the last year — but Djokovic’s lungs and best-of-five aura have been too much for anyone to overcome.

Stevenson: Djokovic is following his own blueprint. He knows Medvedev. Djokovic will focus on what brought him to the final: his mental acumen, his all-court technical consistency and his functional physical being on the court. If Djokovic brings those three to Arthur Ashe, he’ll make history.

Stubbs: His own. No one knows how to win in these moments more than anyone in the history of men’s tennis.

Kumar: Same as always: Wear Medvedev down. Get him running early on in the match. And then break him when he’s tired and can’t keep up. Simple.

Youngmisuk: Djokovic just has to play his game, block out the pressure of making history and do what he does best: get every ball, wear down his opponent and impose his will. If he plays his game up to his normal level and doesn’t let nerves or the moment get the best of him, he should be hoisting No. 21 at the end of the day.

Maine: Djokovic completely dismantled the red-hot Medvedev in the Australian Open final in February, and that’s as custom-made of a blueprint as he’ll find heading into Sunday. He found a way to disrupt Medvedev’s rhythm with a variety of shots and outlasted him in the long rallies. Perhaps most importantly, Djokovic kept his cool throughout and never seemed fazed. If he can repeat that performance, this could be another quick afternoon.

What has been the most impressive part of Djokovic’s run through this season?

Gilbert: His resilience. His problem-solving. His willingness to adapt his game when he needs to.

Connelly: Honestly, the most impressive part is that he hasn’t been at his most impressive. In both of his previous two incredible runs — winning four of five Slams in 2011-12, winning five of six in 2015-16 — he was more dominant from point to point than he is now. This has been harder, and he has found a way to consistently survive and advance.

Stevenson: Of the many impressive moments in the Djokovic season, I think it is the ups and downs of playing professional tennis during a pandemic, testing positive for COVID-19, fighting for political change on the ATP Tour, standing up for lower-ranked players, working on changing his “villain” moniker, winning when it mattered, understanding history and embracing it for the world to see. Djokovic can look to the president’s box and see Rod Laver, who won the calendar-year Grand Slam twice (in 1962 and 1969). Now that is impressive.

Stubbs: Everything! He is a mental and physical giant.

Kumar: His resilience. We all know how last year ended for him. He was defaulted from the US Open after he hit a woman line judge with a ball toward the end of the first set in the fourth-round match against Pablo Carreno Busta. For him to take a step back, calibrate and have this almost perfect year of tennis — he is 27-0 in Grand Slams this year — is quite an accomplishment.

Youngmisuk: He’s relentlessness. Outside of the Olympic meltdown, Djokovic just keeps grinding down his opponents. Perhaps even more impressive is how he has managed to keep winning with the added weight and pressure of making history.

Maine: Having witnessed his meltdown in Tokyo firsthand, I’m most amazed by what he has been able to do in New York after suffering such a disappointment at the Olympics. He was not shy about his desire for the Golden Slam but left the Games empty-handed and with his reputation somewhat damaged due to his unsavory attitude during the bronze-medal match and after.

He then came back to the US Open — from which he had defaulted last year — and has been able to notch impressive win after impressive win and keep his composure, despite the increasing pressure and a weird trend of losing the opening set in the past four matches. It has been quite the emotional turnaround.

Honorable mention: His semifinal win over Nadal at Roland Garros to secure his spot in the French Open final. To beat the King of Clay — the greatest to ever play on the surface — in Paris in four sets was the stuff of legend.

Prediction time: Who will win and why?

Gilbert: I have wanted to see history since we started thinking about this a lot, and I hate to even talk about a perfect game, because that’s what it is. It’s a perfect game and it’s a jinx to talk about a perfect game, but Djokovic is going to win this match, most likely in four sets. Wouldn’t even be surprised if it was straight sets like in Australia.

Connelly: In the “Djokovic vs. the field” competition, I’ve been picking the field for the last two weeks. He had to overcome decent odds and stiff competition just to get to this point. But he’s here. Medvedev is 3-5 lifetime against Djokovic and is in incredible form, but I’m through picking against Djokovic. He wins in four.

Stevenson: I have to believe what Djokovic said post-match after Zverev to Patrick McEnroe: “I’m going to play this [final] like it’s the last match of my career.”

And when Djokovic sits down on the changeover, always staring straight ahead, think Kevin Costner in “For Love of the Game,” on the bench, by himself. And then he pitches a perfect game. Djokovic has been mentally perfect. Djokovic wins, because he’s that good.

Stubbs: Djokovic in five.

Kumar: Djokovic in three. Djokovic has not lost a Grand Slam match — and they’re played two at the Australian Open — to Medvedev. At the 2021 Australian Open, it took him under 2 hours to win his first Grand Slam of the year, beating Medvedev in straight sets (7-5, 6-2, 6-2). He’s in the best form of his life, and Medvedev is not going to pose any new threats to him in the final of what could be the best moment of his career.

It has been 52 years since the last man (Rod Laver) won a calendar-year slam. And on Sunday, Djokovic is sure to join that club.

Youngmisuk: We will see something that has never been done in men’s tennis. Barring an epic meltdown, Djokovic will make history, win his 21st major and complete the calendar-year Grand Slam as well.

Maine: Medvedev’s time is coming, but it’s not this weekend. Djokovic finds his way into tennis immortality by completing the Grand Slam and winning men’s-record-breaking No. 21 in four sets. He has proven that no matter how tough the opponent, he always has just a little bit more. With so much on the line on Sunday, he will not let this elusive opportunity slip by.