Pence homered and drove in three runs on Monday in the Astros' 4-3 win over the NL East leaders. The Houston right fielder went 6 for 13 in the series with three home runs and eight RBIs.
"Not too long ago, I was in the biggest slump," he said. "Now, I've caught a good streak and I'm hitting the ball well."
Pence hit a two-run homer and an RBI double in the finale for the Astros, who've won eight of their last nine home games. Michael Bourn drew a bases-loaded walk from Chan Ho Park to force home the go-ahead run in the seventh inning.
Jose Valverde pitched a perfect ninth for his 22nd save in 26 chances and the Astros matched their longest winning streak of the season at four.
"We got a good start to the homestand," Pence said. "It all starts with pitching. The bullpen did great and we battled as hitters."
The Phillies still have a comfortable lead in their division, but manager Charlie Manuel is worried that his players are starting to press as the team heads into the final month.
"I don't know what it is, if they're tight or whatever," Manuel said. "They have no reason to be tight, but I kind of sense that's what it is.
"This is September 7th. We're still in good position, but we've got to play, man, we've just got to play."
The Phillies scored only 10 runs in Houston and were swept in a four-game series for the first time since August 2008.
"It was a bad series and that's saying it lightly," Manuel said. "We did everything we could to lose. You name it, every game, we did everything we could to lose."
Jamie Moyer became the Phillies' last-minute starter when J.A. Happ was unable to pitch because of a right oblique strain. Moyer got a no-decision after allowing two runs and three hits in six innings.
With the Phillies leading 1-0, Moyer walked Miguel Tejada in the second and Pence drove a full-count pitch over the railroad tracks in left. Pence is hitting .394 with four homers and 10 RBIs in his last 10 games.
"It's just baseball, you can't explain it," Pence said. "Hopefully, I can keep riding it, keep going in there, trying to get a good pitch and making a good swing."
Howard and Ibanez homered in the fourth, the second time this season the two sluggers have connected in consecutive at-bats.
Moyer retired 11 in a row after Geoff Blum's single in the second inning.
Bourn led off the Houston sixth with a line-drive single up the middle that Moyer ducked to avoid. Moyer retired the next three hitters to wrap up his 101-pitch outing.
Park (3-3) relieved Moyer in the seventh and the Astros tied it on back-to-back doubles by Tejada and Pence. Park then walked three straight batters to give Houston a 4-3 lead.
The Phillies had back-to-back homers for the eighth time this season. ... Happ called the injury "a freak thing" and expected to make his next scheduled start this weekend. "I'd be really frustrated if I did try to go today and suddenly, it's six or seven starts instead of one or two," he said. "It's just a frustrating situation." ... The Astros purchased the contracts of infielder Chris Johnson and right-handed pitcher Billy Sadler and recalled infielder Tommy Manzella from Triple-A Round Rock. ... Astros slugger Lance Berkman has not homered in 30 games, the second-longest drought of his career.