Milwaukee starter Carlos Villanueva retired the first 11 Houston batters in order and held the Astros to a single through four innings.
Trailing, 4-0, in the fifth, the Astros got on the board when Pence drilled a 1-2 fastball from Villanueva into the right-field seats for a two-run homer. Pence's shot scored Lee, who led off the inning with a double to left.
"We're definitely starting to see the capabilities of this offense," Pence said. "You can talk about it all day long, but you've got to go out and do it, [and] if we can keep this going, we've got a chance."
In the sixth, Kazuo Matsui beat out an infield hit, bringing Tejada to the plate.
Tejada, who had promised young fan Jacob Scott during a Muscular Dystrophy Association reception earlier in the day that he would hit a home run for him that night, delivered his fifth homer of the year on an 0-1 fastball from Villanueva (1-3) to tie the game. Scott, who threw out the ceremonial first pitch, watched as Tejada circled the bases.
"I was so excited," Tejada said. "I was excited when I hit the home run. I know it's hard to promise someone a home run and then hit it. Today when I went to lunch with this kid, I wanted him to be happy."
Berkman followed with an opposite-field shot to the left-field seats for his ninth homer of the season. Lee drove a 2-2 pitch from the Brewers right-hander for a homer to left to make it 6-4 and chase Villanueva.
It was the first time the Astros hit three consecutive homers since Carlos Beltran, Jeff Bagwell and Berkman did it off Cincinnati's Aaron Harang on Aug. 31, 2004. The five homers were the most by the Astros in a game since they hit six against Pittsburgh on Aug. 9, 2006.
"We probably won't go back-to-back-to-back the rest of the year; that's a fairly rare feat," Berkman said. "But we have guys that are capable of doing that. I mean Carlos can hit the ball out of the ballpark at any time, so can Miggy and I like to think I have pretty good power."
Astros ace Roy Oswalt (3-3) won his third consecutive decision. The right-hander went six innings and allowed four runs (three earned) on six hits and four walks. Oswalt struck out six.
"I don't think he had his best stuff tonight, but he kept us in the ballgame," Cooper said.
Oswalt agreed with that assessment.
"Curveball still ain't there all the time," the righty said. "Last game it was OK. Tonight it was kind of popping out of my hand again, [but the] last inning, [it] felt great."
Mike Cameron led off the fifth with his first homer of the season to give Milwaukee a 3-0 lead.
"I didn't want to walk him," Oswalt said. "The 3-2 pitch was right down the middle."
The Brewers added another run in the inning when Tejada tried to make a barehanded grab of J.J. Hardy's slow roller with the bases loaded.
Tejada couldn't come up with the ball, allowing Hardy to reach first with an infield single as Prince Fielder scored on the play to make it 4-0 Milwaukee.
"I wanted to get a double-play ball there; he hit the ball on the ground, but it was too soft," Oswalt said.
Oswalt allowed only two hits during the first four frames, but one of them was a two-run homer by Ryan Braun in the first. Braun's blast to right scored Rickie Weeks, who reached second on a pair of Matsui errors.
Pence picked up his second homer of the night and third of the season when he hit a David Riske slider out of the park to left-center.
For the third consecutive game, the Astros scored at least six runs. And with third baseman Ty Wigginton, who came off the disabled list on Friday, going 1-for-4, they have their lineup intact.
"Certainly the team that [general manager] Ed [Wade] put together ... really the first time we've had everybody out there at the same time," Berkman said. "That having been said, I think we have one of the best benches in baseball. We've got three or four guys on our bench that could start for any other team in the league."