HOUSTON (AP) -- Brett Lawrie hit a tiebreaking RBI single in the sixth, and the Oakland bullpen combined for 4 2-3 scoreless innings as the Athletics snapped a four-game losing streak with a 2-1 victory over the Houston Astros on Monday night.The loss snapped Houston's five-game winning streak.Lawrie's hit came off Will Harris who came on in relief of Joe Thatcher (0-1), who gave up an infield single and two walks to load the bases with no outs.Edward Mujica (2-1) went 1 2-3 innings for the win, Evan Scribner threw two innings and Tyler Clippard pitched the ninth for his fourth save. Harris escaped further damage in the sixth, getting Sam Fuld to ground back to the pitcher for a force at home and then Eric Sogard to hit into a double play.Oakland starter Drew Pomeranz left the game in the fifth inning with left shoulder tightness. After throwing a pitch and then backing off the mound, manager Bob Melvin went out to the mound with the trainer, and Pomeranz was taken out. He went 4 1-3 innings, giving up one run and two hits with five walks and two strikeouts.Evan Gattis' sacrifice fly scored Jose Altuve to give Houston a 1-0 lead in the first, but Sogard's RBI single in the second tied it.George Springer sent a deep drive to center in the eighth, but Fuld made a catch running up Tal's Hill.Lance McCullers of the Astros allowed one run and three hits with five strikeouts but walked three in 4 2-3 innings in his first career start.