"I thought he hung in there pretty well," Astros manager A.J. Hinch said. "First-night adrenaline pumping, he had his pitches, made some really good pitches for strikeouts. And he had a swing-and-miss strikeout on every pitch -- fastball, his big breaking ball and his changeup.
"So you know he'll get more pitch efficient as he gets away from the first-game adrenaline, but all in all, we obviously want to get five [innings] out of him. He came close to that, but for a Major League debut, with all the attention on him, I thought he handled himself very well."
McCullers (21 years, 228 days) became the youngest Astros player to make his debut since Jose Altuve (21 years, 75 days) on July 20, 2011. He's the sixth starting pitcher in club history to allow one run or fewer in his Major League debut.
"I felt good, I felt relaxed, I felt in a pretty good state of mind," McCullers said. "I'm just focusing more on being happy and relaxed and understanding that less is more in those early innings."
McCullers -- who sported cleats featuring a Batman logo -- flashed his plus-fastball out of the gate, throwing a 94-mph pitch to Coco Crisp to start the game. The only run he allowed came on a two-out single by Eric Sogard in the second, and later in the inning he retired Marcus Semien to strand the bases loaded. That was the beginning of a stretch in which he sat down nine in a row.
"I felt good the whole game," he said. "Like I said, I struggled a little bit with my put-away pitches in the second, but I know I have a great defense behind me, and from the third [inning] on, I just trusted them a lot and was just giving the other team an opportunity to put the ball in play."
The 1-2-3 third inning after he labored in the second was a great sign, Hinch said.
"I loved how he competed, gave us what he had for as long as he could," the manager said. "There's going to be a day where he's got plenty left in the tank to get through that fifth inning. Tonight wasn't that night, but I was proud of him."
McCullers went 3-1 with a 0.62 ERA in six games (four starts) at Double-A Corpus Christi, allowing 15 hits and two earned runs in 29 innings. He struck out 43 batters and walked 11. He's the son of former Major League pitcher Lance McCullers, who was in the stands on Monday.
"A lifelong dream is to pitch in the big leagues, and I got to accomplish that, and no matter what happens from this point on, it can't be taken away," Lance Jr. said. "I feel really blessed and fortunate for the opportunity."