"The difference in the game today was the way Brandon Backe came out and set the tone for us, the bullpen shut the door and Valverde probably did one of the most amazing things I've ever seen on a baseball field," Pence said.
Valverde was hit in the face by a ball hit by Pedro Feliz during the ninth inning.
Feliz lined a 1-2 pitch that glanced off Valverde's glove and then the side of the right-hander's face. Valverde fell to the ground and play was halted briefly while Astros assistant athletic trainer Rex Jones examined Valverde.
Valverde got up, took some warmup tosses and went on to record his 15th save in 18 chances.
"I feel good right now, everything is good," Valverde said. "I felt a little dizzy. I said you know what, I have to be in the game. Thank God it hit my glove first. If that didn't happen, I don't know where I would be right now."
With the scored tied at 1 in the seventh, Pence powered a 3-0 fastball from Phillies starter Adam Eaton (0-3) into the left-field seats to give the Astros their first lead of the night.
"It was over the plate, [I was] just trying to get the barrel of the bat on it and happened to," Pence said.
Two outs later, the Astros added an insurance run on Michael Bourn's RBI single to right.
"I think at some point in time, he's going to become a a guy like that who can hit 25 and drive in 100," Astros manager Cecil Cooper said. "And maybe even one day get to be a 30-30 guy, because he can run, he definitely has power and he has power to all fields, as he showed tonight. Hunter's starting to swing the bat really good. The last two or three weeks, you can tell he's coming on a little bit."
Backe (4-5) turned in his third consecutive quality start by holding the Phillies to six hits and a walk in 7 1/3 innings. The right-hander struck out six while recording back-to-back victories for the first time this season.
"The whole game I felt pretty good, felt pretty much under control, [it] got a little hairy in the third inning. Other than that, I felt pretty good," Backe said. "The repetition [has helped], the amount of pitches I've thrown this year [is helping] find the strike zone and keeping the ball in there."
"Probably his best performance by far this year," Cooper said. "That's about as good as I've seen Brandon throw. First time this year he's gotten into the eighth inning."
Pence went opposite field with an 0-1 fastball from Eaton leading off the fifth for his sixth home run of the season.
The Phillies had gone ahead, 1-0, in the second when Pat Burrell hit the first pitch he saw from Backe into the left-field seats for his 12th home run.
The Phils loaded the bases with two outs in the eighth, but reliever Doug Brocail retired Ryan Howard on a grounder to first to end the threat.
"I hate loading the bases; I wanted to talk about it," Brocail said. "I didn't have the sense that he [Chase Utley] was going to completely take, [so] once we fell behind, it put me in a better spot of not having to go back into the count. [Howard] helped us out, he got himself out and I'll take that any day of the week."
Said Cooper: "We're going to be careful there because I respect Ryan Howard a lot, but Utley to me is probably their best hitter. When you can avoid their best guy, you know you try to do it. You don't want to walk the lead run to first, but you've got to be very careful there."
Valverde stranded the potential tying run in the ninth by retiring Shane Victorino.
"Brocail came in and made some big pitches," Cooper said. "What can you say about Valverde? Pretty incredible. I was just hoping he was OK."