"Chen did a good job of keeping us in the game," Davis said. "To hold that offense to two runs is saying something, and we were able to get timely hits when we needed it."
Chen left with a 3-2 lead, and the bullpen made it stand up. Johnson retired Derek Jeter and Ichiro Suzuki on grounders and struck out Alex Rodriguez to end it in front of a rollicking crowd at Camden Yards.
Much earlier, Suzuki's deft dancing at the plate put the Yankees ahead.
Pettitte, whose 19 wins and 43 starts are the most in postseason history, allowed three runs and seven hits in seven-plus innings.
"I thought he pitched a really, really good game," Girardi said. "I thought he had really good command of his fastball, his curveball, really all his pitches."
Pettitte came out of retirement before this season hoping to pitch again in the playoffs. He was effective; Chen was just better.
"It's a playoff game," Pettitte said. "If you give up too many runs, that number doesn't have to get too high until you know you're going to get a loss."
Pettitte, however, got little offensive backing. New York stranded 10 and went 2 for 8 with runners in scoring position.
"They were tough. We weren't able to get the big hits with runners in scoring position," Pettitte said. "It was a frustrating game and one you hate to lose. It would have been nice to get this one, that's for sure."
After Davis hit a two-run single to put Baltimore up 2-1 in the third inning, Matt Wieters led off the sixth with a double and scored on a single by Reynolds to make it 3-1.