Dustin Garneau provided a key hit and Tanner Roark fired five strong innings in their Oakland debuts Sunday afternoon, propelling the Athletics to a 4-2 victory and a two-game series sweep of the visiting St. Louis Cardinals.

Jurickson Profar chipped in with a home run and five Oakland relievers combined for four innings of one-run support, helping the A's complete a four-game whitewashing of the Cardinals in the interleague season series.

Garneau, picked up off waivers Saturday from the Los Angeles Angels, made Cardinals starter Adam Wainwright (7-8) pay for two hit batsmen with a two-out, two-run double that allowed the A's to take the lead for good at 2-1 in the fourth inning.

Wainwright had hit Mark Canha and former teammate Stephen Piscotty consecutively one out earlier.

The Cardinals' Paul DeJong had opened the scoring in the top of the inning with a solo homer, his 19th of the season, off Roark.

Profar's homer, a solo shot with one out in the sixth, produced the eventual winning run, giving Oakland a 3-1 lead. It was his 15th of the season and came on Wainwright's final pitch.

The veteran right-hander was pulled after allowing three runs and six hits in 5 1/3 innings. He walked three and struck out seven.

Roark (1-0), who was 6-7 with Cincinnati before being acquired at Wednesday's trade deadline, went five innings, allowing one run and four hits. He walked two and struck out six.

The Cardinals rallied within 3-2 in the eighth when Kolten Wong greeted Jake Diekman with a two-out, RBI single.

But Joakim Soria came on to get Jose Martinez to fly out with the potential tying run on base, before A's closer Liam Hendriks worked a 1-2-3 ninth with two strikeouts for his 11th save.

The A's tacked on an insurance run in the last of the eighth on two walks, an infield out and a wild pitch by John Gant.

Garneau finished 2-for-3 and Marcus Semien also had two hits, including a double, for the A's, who completed a 6-3 homestand with a third straight win.

The Cardinals, who were making their first Oakland appearance since 2013, lost for the fifth time in their last seven games.

--Field Level Media