Right-hander Mike Fiers ran his unbeaten streak to 16 games, and Chad Pinder broke open a tight contest with a pinch-hit, three-run home run Saturday night, as the Oakland Athletics thumped the visiting St. Louis Cardinals 8-3 in the opener of a two-game interleague series.

Mark Canha had a two-run single, while Marcus Semien and Chris Herrmann scored twice apiece for the A's, who won their fifth straight against the Cardinals, including three in a row this season.

Pitching with a lead from the second inning on, Fiers (10-3) checked the Cardinals on six hits over 5 2/3 innings. He allowed one run and one walk, striking out four.

The 34-year-old improved to 8-0 in his last 16 starts overall and 5-0 in his last nine home outings.

The A's jumped on right-hander Dakota Hudson (10-6) for two runs in each of the first two innings. Canha's two-run hit got the scoring going in the first, before a sacrifice fly by Robbie Grossman and a passed ball plated two more Oakland runs in the second.

Down 5-0 entering the sixth, the Cardinals got within three with an RBI single in the sixth by Paul DeJong and an RBI groundout by Tommy Edman in the seventh.

But after a pair of two-out walks in the last of the seventh, Pinder greeted reliever Tyler Webb with his 10th home run of the season to make it 8-2.

Hudson didn't finish the fourth inning, charged with four runs (three earned) on five hits. He walked five and struck out seven.

Cardinals pitchers allowed 11 hits and served up eight walks in the loss.

Lane Thomas capped the scoring with a pinch-hit home run, his second of the season, leading off the ninth.

The win was Oakland's fifth in its last six games and clinched a winning nine-game homestand with a fifth win in the first eight games.

DeJong and Paul Goldschmidt had two hits apiece for the Cardinals, who were playing at Oakland for the first time since June of 2013.

--Field Level Media