Tanner Roark pitched five innings of one-run ball, and the Athletics beat Adam Wainwright and the St. Louis Cardinals 4-2 on Sunday.
Jurickson Profar connected for his 15th homer as the A's won for the sixth time in seven games. Dustin Garneau had two hits and two RBIs after he was claimed off waivers Saturday.
Roark (7-7) allowed four hits, struck out six and walked two. He pitched out of a pair of jams in his first start since he was acquired in a trade with Cincinnati at Wednesday's deadline.
The Cardinals twice had two on and two out against Roark but failed to score each time. Ozuna struck out in the third, and Matt Carpenter struck out swinging in the fourth.
Roark fanned Marcel Ozuna after a 14-pitch battle against Goldschmidt. The NL Player of the Month for July, Goldschmidt fouled off eight consecutive pitches before drawing a walk.
Liam Hendriks retired three batters for his 11th save.
St. Louis fell 1 1/2 games back of NL Central-leading Chicago, which swept Milwaukee with a 7-2 victory.
Wainwright (7-8) struggled with his command most of the afternoon. The right-hander hit two batters, walked three and allowed three runs in 5 2/3 innings.
Paul DeJong homered for the Cardinals, who lost each of their four games against the A's this season.
Carpenter was 1 for 5 with two strikeouts in his first game back off the injured list. Carpenter missed 17 games with a bruised right foot.
Profar connected in the sixth, belting a towering drive that landed midway up the staircase beyond the wall in right field.
Michael Wacha (6-4, 5.15 ERA) returns to the starting rotation against the Dodgers on Monday. Wacha pitched out of the bullpen in his three previous appearances.