PHOENIX — First they took down the National League Central champions. Then they knocked out the NL West champions. Of all the rousing Arizona Diamondbacks victories this October, though, their 6-5 come-from-behind win in Game 4 of the National League Championship Series on Friday against Philadelphia might have best illustrated who the Diamondbacks are.

Not the most well-known. Not the most talented. But in baseball, in the crapshoot that is the postseason, none of that matters.

“Hopefully when we do things like this,” Diamondbacks manager Torey Lovullo said, “the baseball world sees that the Arizona Diamondbacks are a damn good baseball team.”

How could anyone conclude otherwise after Arizona tied the series Friday? It wasn’t just the dramatic, score-tying, pinch-hit two-run home run from outfielder Alek Thomas off Craig Kimbrel in the eighth inning or the go-ahead RBI single from catcher Gabriel Moreno four batters later. Short on starting pitching, the Diamondbacks cobbled together a bullpen game that could have spiraled into a disaster but instead kept the score close enough for the team’s too-young-to-know-any-better core to deliver.

Thomas, Moreno, All-Star outfielder Corbin Carroll and shortstop Geraldo Perdomo are all 23 years old — and each has excelled at some point this postseason in which the Diamondbacks went from the team with the worst record on the field to two wins from the World Series.

“There’s a lot of excitement in that clubhouse,” Lovullo said. “We have a lot of 23-year-olds that go out and perform at a high level, and then when it’s time for them to act like 23-year-olds, they do. And that’s a lot of fun for me to watch. It’s a great moment for this organization.”

The moment was particularly satisfying for Thomas, who in May was demoted to Triple-A, where he spent a month. He returned and played well enough to earn a nomination as a Gold Glove finalist in center field, but after going hitless in Philadelphia, where the Phillies won the first two NLCS games, Thomas started on the bench in Games 3 and 4. He pinch-ran Thursday and scored the game-tying run in the first comeback win of the series. And he entered Friday’s game with an even more acute opportunity.

Kimbrel, who had allowed a walk-off hit the previous night, entered in the eighth inning of Game 4 with Philadelphia ahead 5-3. He promptly allowed a leadoff double to Lourdes Gurriel Jr. Following an Evan Longoria lineout, Thomas came in for third baseman Emmanuel Rivera — a move that almost didn’t happen, as Lovullo considered saving him for later in the game and using rookie Jordan Lawlar to bunt.

He stuck with Thomas, whom Kimbrel worked inside with curveballs and fastballs until the count ran full. On the sixth pitch of the at-bat, Kimbrel tried to paint a 94-mph fastball on the outside corner. Thomas pulled it anyway, and it flew 412 feet into the night, landing in the pool over the right-center-field fence at Chase Field, where the crowd of 47,806 erupted, doing its best imitation of the Citizens Bank Park crowd that has buoyed the Phillies all October.

“I trust Torey and I trust the coaching staff,” Thomas said. “So just stay ready at all times. And that’s what I was doing. Definitely not going to hang my head about not being in the lineup, but I knew at some point they were going to call me and just got to be ready.

“A lot of people didn’t think we would be here, and honestly none of that mattered,” Thomas continued. “We believed in the guys in the clubhouse and our coaching staff and everybody in the Arizona Diamondbacks organization. Definitely just a crazy, crazy season, crazy playoffs.”

The wild ending capped a phenomenal day of baseball that included the Houston Astros moving to within one win of the World Series. The Phillies looked as if they’d wind up there, too, particularly as Arizona stumbled in the middle innings. The starting-pitching matchup did not exactly suit the heft of the game. Philadelphia’s Cristopher Sanchez hadn’t started a game in 26 days. Arizona’s Joe Mantiply is a left-handed reliever. Both put up zeroes in the first before Arizona scratched runs across in the second and third, chasing Sanchez and beginning a parade of eight pitchers for Philadelphia. The Diamondbacks matched them, with Kyle Nelson and Miguel Castro allowing runs in the fourth (Kyle Schwarber’s 19th postseason home run, a record for left-handed hitters) and fifth innings to tie the score.

Philadelphia took control in the sixth. Rookie left-hander Andrew Saalfrank, so good since his September debut, walked the bases loaded to begin the inning. Rivera bounced a throw to Moreno at home on an Alec Bohm groundball, and it kicked away, allowing a pair to score and staking the Phillies to a 4-2 advantage. The teams traded runs in the seventh before the eighth-inning implosion by Philadelphia’s bullpen.

“Belief is a very powerful thing,” said Longoria, the team’s wizened veteran at 38. “So I think we kind of proved that in the first two series, just really clicking and putting pressure and continuing to do that. Now that we’re in the NLCS, it’s like we’re starting to get back to what we were doing in those first couple series, and that’s a scary thing.”

Scariest, for Philadelphia, is how quickly its cloak of invincibility has been pierced by a group that is too young to know how precocious it is.

“Their payroll is higher than ours,” Perdomo said. “They’re good. They’re really good. If you see our lineup, it’s a lot of guys who are 23. But we can play with them. We’re showing that.”

They’ll get a chance to show it again in Game 5 on Saturday night, with about as good of a starting-pitching matchup as October can offer: Phillies ace Zack Wheeler against Diamondbacks ace Zac Gallen. In Game 1 of the series, Wheeler twirled six excellent innings — the only blemish was a Perdomo two-run homer — while the Phillies touched up Gallen for three home runs in the first two innings.

With both bullpens drained by the past two days, no game this postseason may rely more on the starters than Game 5.

“I’d be shocked if that one’s 6-5,” said Diamondbacks closer Paul Sewald, who struck out three in the ninth to secure the save in Game 4. “It’s going to be a bad day to be a hitter with those two guys, but maybe 2-1 wins it.

“And we are as scrappy as anybody.”