"Especially the way he pitches here," Bumgarner said. "You knew you weren't going to have a whole lot of room for error."
The Giants had five baserunners all game. The Phillies had five baserunners before there was an out in the second inning.
Bumgarner got out of a bases-loaded situation in the first inning but paid the price in the second inning, giving up a bases-loaded double to Michael Young.
"It was a great game, two of the best lefties in the league," Young said. "Bumgarner is real tough. We were happy to have some decent at-bats and fortunate to string some runs together."
Hunter Pence hit a home run with one out in the second, ending Lee's 21-inning scoreless inning against the Giants. Pence collected three hits, of five total, against his former Phillies team, and scored both of the runs. Pence was facing the Phillies for the first time since they traded him to the Giants last July.
"Pence had a nice night but it was rough for the rest of the guys," Giants manager Bruce Bochy said. "A game like this, you have to pitch well and play a good, clean game. We didn't play so well. It gets back to we faced a tough pitcher and he shut us down."
Bumgarner (3-1) took his first loss of the season with statistically his worst effort of the season.
"My command was not as sharp as it has been," Bumgarner said. "I thought I made good pitches, and they didn't miss. I needed to go deep into the game to help the bullpen, but I would have liked to have gone a little further."
Bumgarner allowed season highs of five runs and eight hits in six innings. He walked two and struck out seven. He had allowed seven runs combined over his first six starts.
"He wasn't as sharp as he's been every game but you can't expect him to be," Bochy said. "There was one play we don't quite handle and they get three runs out of it."
Lee improved to 5-0 in six regular-season starts against the Giants, giving up just his fourth and fifth runs in 51 innings against them, an 0.88 ERA.
With two out in the first, Young and Ryan Howard singled and Delmon Young walked to load the bases. Bumgarner got Domonic Brown on a comebacker to end the threat.
In the second, John Mayberry singled and Erik Kratz hit a ball that Marco Scutaro had trouble handling after flagging it down. Lee sacrificed both runners along and Chase Utley walked to set up Michael Young's double. Utley eventually scored on a wild pitch.
"I didn't make the pitches I needed and he hit them," Bumgarner said of Young. "That's what makes him so good. He's one of the best hitters in the game. That team has a lot of good hitters."
The Phillies added two more runs in the fifth. Young led off with a double and scored on Delmon Young's sacrifice fly. Brown followed with a home run.
The Giants added their second run in the eighth, with Pence scoring on a throwing error.
The Phillies turned three double plays in support of Lee and the Giants did not leave a runner on base for the first time since 2008.