HOUSTON -- Clubhouse workers packed the Pirates' bats into bags as they prepared to load them onto the team bus following an 8-2 loss to the Astros on Sunday.

Unfortunately, the Bucs hadn't been able to do much with them since the fourth inning. After the Pirates had built a 2-1 in that frame, they managed only one hit the rest of the game.

"We have to swing the bats better," manager John Russell said. "That's the bottom line. We've shown signs that we can, but to go out and get three, four, five hits -- it's going to be tough to win."

Sunday's loss completed a 0-9 season for the Bucs at Minute Maid Park, and it followed a common script of the previous two losses there: Get an early lead, lose it in one inning and shut it down offensively the rest of the game.

"We're putting a lot of pressure on our pitching staff," Russell said. "It showed." Jeff Karstens was the latest starter to experience an inning that got away from a Pirates pitcher. Friday it came in the eighth to Evan Meek, and Saturday in the seventh to Paul Maholm.

This time, the Astros didn't wait as long to knock Karstens around. With the Pirates still leading in the sixth, right fielder Hunter Pence doubled. After a delay when left fielder Carlos Lee hit home-plate umpire Alan Porter on his backswing, causing Porter to leave the game, Pence advanced to third on a Lee flyout. He then scored on a Jeff Keppinger sacrifice fly to tie the game at 2.

Karstens now had a clean slate with two outs and the bases empty, but his troubles were just beginning. He hit first baseman Brett Wallace with a pitch and then gave up a single to third baseman Chris Johnson, who scored the go-ahead run on a Jason Castro single.

"It just seemed like three batters real quick changed the game," Karstens said.

And Karstens didn't make it through the inning, just as Meek and Maholm hadn't on the previous two nights. Russell replaced him with Sean Gallagher, but Gallagher was ineffective, giving up a double to pinch-hitter Pedro Feliz to make it 5-2.

"We had a 2-1 [lead] again and I wasn't able to hold it," Karstens said. "But there was a lot of positives I can take from it."

The same positives could be taken by the Pirates' hitters. After they scored those two early runs off Astros starter J.A. Happ, they didn't have much success. In the sixth, Happ walked Bucs third baseman Pedro Alvarez and second baseman Neil Walker. Right fielder Lastings Milledge then hit a grounder that he beat out at first to momentarily avoid a double play, but Alvarez tried to score from second on the play and was out by a wide margin to end the threat. That was as close as the Pirates would get the rest of the game.

"He was effectively wild," Russell said of Happ. "I'm not taking anything away from Happ, we just have to swing the bats better."

The Pirates' lone tallies came in the fourth. Left fielder Jose Tabata singled and Alvarez walked. Second baseman Neil Walker moved both runners over with a sacrifice Milledge tied the game with a single. Catcher Chris Snyder then hit a sacrifice fly to give the Pirates a 2-1 lead.

The loss was the seventh straight for the Pirates, who return home after an 0-6 road trip to face the Marlins for the first of a four-game set Monday night at PNC Park.