HOUSTON -- Brewers closer Eric Gagne was not going to blame anyone but himself for another disappointing finish.

Gagne surrendered two ground-ball hits and walked three batters in ninth as a two-run lead slipped away, and the Astros won it three innings later. Hunter Pence hit a two-run home run in the 12th for an 8-6 win over the Brewers at Minute Maid Park that finished a three-game sweep.

Outfielder Mike Cameron drove in four runs with a pair of home runs, and Ben Sheets improved over his previous start and even knocked a rare RBI double. But Lance Berkman drove in four runs in his 15th career four-hit game for the Astros and drew the walk that handed Gagne his fifth blown save.

"You put yourself in that situation. I'm not going to blame anybody," said Gagne, who appeared to have trouble with a couple of calls from plate umpire Phil Cuzzi, and didn't get another close call at first base. "I made some good pitches, some bad pitches, and I walked a guy where I shouldn't have walked a guy. I put myself in a situation I shouldn't have been."

Mitch Stetter (1-1) took the loss after allowing Pence's home run to left field, and Houston's Tim Byrdak (1-0), who retired J.J. Hardy on a bases-loaded flyout in the top of the 12th inning, was the winner.

The Brewers took a 6-4 lead into the bottom of the ninth. With one out, pinch-hitter Darin Erstad hit a single up the middle and another pinch-hitter, Geoff Blum, legged out an infield hit to second baseman Rickie Weeks, who made a nice play to get to the baseball before it rolled into right field, but couldn't get enough on his throw.

"It was bang-bang. Could have gone either way," manager Ned Yost said.

Gagne then walked Michael Bourne to load the bases and retired Kaz Matsui on a groundout that scored a run. Miguel Tejada walked to load the bases again and so did Berkman, forcing in the tying run.

Carlos Lee grounded out to end the inning, but not before the damage was done. In his previous five outings before Sunday, Gagne had not allowed a run.

The close calls on some of Gagne's pitches -- he especially struggled to locate his changeup -- had nothing to do with the result, Yost said. "There were some calls that could have gone either way that we thought we strikes," Yost said. "But not the majority of them. We're talking two or three pitches."

"We played a very good ballgame," Gagne said. "I came in and messed it up."

Before the ninth, Sheets was in line for his fifth win vs. no losses. He showed an ability to bend but not break, allowing four runs on seven hits, and exited in the seventh inning with six strikeouts, giving him 1,080 for his career and leaving him one shy of Teddy Higuera's franchise record.

Corey Hart's RBI single gave the Brewers a 1-0 lead against Astros starter Chris Sampson, who got out of a potentially big inning when the Astros cut off the throw home and caught Prince Fielder between second and third base.

Bill Hall doubled leading off the second inning, moved to third on a groundout and scored when Sheets yanked a double into the left-field corner. It was the pitcher's first hit since June 19 of last season and just his second career double. The other came May 16, 2002, off Reds reliever Chris Reitsma.

Sheets entered the game 0-for-11 at the plate this season, and 28-for-377 (.074) in his career, with eight RBIs.

But then, in what proved a key play as the teams played extra innings, Sheets was out on a close play at home plate. He hung up just short of third base to make sure Jason Kendall's double to left field would fall in, and Astros outfielder Lee initiated a perfect relay to barely get Sheets.

Sheets didn't slide. Even so, it was as close a play as they come.

"I knew it was going to be close," Sheets said. "[Third-base coach Dale] Sveum let me know it was going to be close. I haven't slid in forever. We work on it a little bit, but it's not like the game."

Should he have slid?

"Of course he should have slid," Yost said. "Come on, we're playing baseball. Yes, he should have slid, but Benny gets on base so few times that it really was like foreign territory."

On the mound, Sheets was much sharper on Sunday than last week in Chicago, when he set a career high with seven walks after missing his previous start with a tight triceps. But he couldn't figure out Berkman, who homered leading off the second inning just after Sheets ran the bases, hit a two-out, two-strike RBI double in the third and another in the fifth that came two batters after left fielder Ryan Braun missed a backhanded stab at a Matsui fly ball for an RBI double.

Berkman improved to 21-for-60 (.350) against Sheets, including his fifth career home run.

"I wasn't a lot better," Sheets said of this start vs. his last. "I was better. I didn't have great command, especially with two strikes."

Berkman's third RBI hit cut Milwaukee's lead to 6-4, and it held up into the ninth. Sheets retired the final five hitters he faced, including pinch-hitter Mark Loretta leading off the seventh, and Brian Shouse retired Michael Bourn and Matsui to end that inning.

Guillermo Mota took the eighth and mowed through the dangerous heart of the Houston order. Tejada led off with a sharp single that lined off shortstop Craig Counsell's glove, but Mota retired Berkman on a long flyout, Lee on a fielder's choice and Pence on a strikeout to end the inning.

Gagne was not as successful.