Houston, TX (SportsNetwork.com) - Drew Pomeranz and three relievers combined on a two-hitter as the Oakland Athletics downed the streaking Houston Astros 2-1 in the opener of a three-game AL West series.

Brett Lawrie drove in the go-ahead run in the sixth inning, and Edward Mujica, Evan Scribner and Tyler Clippard combined for 4 2/3 hitless frames to end Oakland's four-game skid.

The A's pulled Pomeranz in the fifth even though he had surrendered just one run. He did, however, walk five and left with left shoulder tightness.

Mujica (2-1) relieved Pomeranz and stranded a pair in the fifth to pick up the win, just the second in the last 12 games for the cellar-dwellers.

The first-place Astros had won five in a row coming in and welcomed a new starter to the fold. Lance McCullers did not last five innings in his big- league debut but only allowed one run. Houston's promising 21-year-old, who boldly wore Batman cleats, made the jump from Double-A and scattered three hits and three walks and struck out five.

"I felt like it went pretty well," McCullers said. "I feels more real now after the game that I pitched a game in Minute Maid Park for the Astros."

The only run the Astros managed came on Evan Gattis' sacrifice fly in the first inning.

Eric Sogard tied the game with a two-out RBI single in the second, and Lawrie knocked in the deciding run with the bases loaded in the sixth. Joe Thatcher (0-1) was pulled after putting the first three hitters on, and Will Harris limited the damage to Lawrie's single through the right side.

Sam Fuld robbed George Springer of extra bases in the eighth inning with a snowcone catch on Tal's Hill, and Clippard retired the side in order in the ninth to complete a dominant bullpen effort and notch his fourth save.

"We proved to ourselves we can (win close games)," said Clippard, whose club came in 1-13 in one-run games this season. "It was exactly what we needed."

Game Notes

McCullers was 3-1 with a 0.62 earned run average over six games -- four starts -- at Corpus Christi before his callup ... The A's committed an error for the 15th straight game, the club's longest streak since 1982 ... Pomeranz has not lasted past the fifth inning in any of his three starts against the Astros this year.