HOUSTON — The Astros quickly ran out of superlatives in describing Justin Verlander‘s performance in their 4-2 victory over the New York Yankees in Game 1 of the American League Championship Series on Wednesday night.

Echoes of “first-ballot Hall of Famer” and “ace” were heard throughout the Astros clubhouse after Verlander struck out 11 batters over six innings and allowed only one earned run.

But what truly differentiated his performance was the fact that the 39-year-old Verlander was not initially sharp, coming off one of the worst postseason outings of his illustrious career, having allowed six runs on 10 hits in the first game of the division series against the Seattle Mariners.

The Astros managed a comeback victory against Seattle with a three-run, walk-off home run by slugger Yordan Alvarez, with Verlander notably showing rust and lack of command. Even so, it was no surprise to catcher Martin Maldonado that his ace quickly returned to form when he was needed most.

“This is exactly what I expected from him,” Maldonado told ESPN. “That is why he is a Hall of Famer.”

“He’s not only physically strong, which you can see, but he’s mentally strong,” manager Dusty Baker added in praise of Verlander. “This guy, he has mental toughness. When he’s down and out and it looks like you got him in trouble, I mean, this guy, he can dial it up.”

While the Astros fell behind in the second inning Wednesday night after Harrison Bader tagged him with a solo shot, Verlander bounced back, retiring the last 11 Yankees he faced in a row, with nine punch-outs.

Verlander’s 11 total strikeouts gave him the eighth double-digit strikeout game of his postseason career, setting an MLB record. Verlander also became the new postseason strikeout king, setting a major league record with 219 career strikeouts in the playoffs, surpassing Clayton Kershaw‘s 213.

“I think you saw what a real Hall of Fame pitcher’s made of tonight,” fellow starter Lance McCullers Jr. said. “He had a tough start in the DS. You don’t have to beat around the bush; it wasn’t a great start. I know he wanted to do better. … You saw him work all week. He felt like he had some adjustments to make, and he made the adjustments. … In a series where there’s only one off-day, him being able to give us six amazing innings, speaks volumes for who he is as a pitcher and a competitor.”

The Yankees finished the game with 17 strikeouts, tied for the second most in a nine-inning game in postseason history. With the Astros striking out only twice, their differential of 15 strikeouts became the largest in a single game in postseason history.

“He gave us exactly the kind of performance we needed, and I feel that I say that all the time about Verlander,” said Jose Altuve, who is stuck in the longest postseason slump of his career at 0-for-19. “This was a huge win for us, alongside our bullpen, which has been exceptional all season. He set the tone and allowed us to win the first game, which is very important in a tough series like this one, and against a great team like the Yankees.”

Verlander improved to 5-1 with a 2.62 ERA in nine career postseason starts against the Yankees. This was Verlander’s 15th career postseason win, tying Hall of Famer John Smoltz for second all-time (Andy Pettitte leads with 19).

The Astros improved to 10-5 all-time in postseason play against New York, including a 7-1 record at Minute Maid Park.