Mike Fiers tossed six strong innings and Tommy La Stella and Jake Lamb had two hits apiece to pace the Oakland Athletics to a 3-1 victory over the Colorado Rockies on Wednesday in Denver.

Lamb also drove in a run and Liam Hendriks picked up his 13th save for Oakland (31-19), which increased its lead to six games over Houston with 10 games remaining.

The Athletics also snapped a six-game losing streak against the Rockies.

Raimel Tapia and Tony Wolters had two hits apiece for Colorado, which lost vital ground in its push to reach the postseason for the third time in four seasons. The Rockies (22-26) have lost six of their last eight and fell 1 1-2 games.

The A's scored first thanks to some lack of control by Colorado starter German Marquez. Tony Kemp led off the third inning with a walk and went to second on an errant pickoff attempt by Marquez. Marcus Semien walked, and a passed ball on ball four allowed Kemp to get to third.

Kemp scored when Robbie Grossman grounded into a forceout to give Oakland a 1-0 lead.

The Rockies came back in their half of the third inning. With one out Ryan McMahon, Wolters and Tapia singled to tie it, but Wolters was stranded at third.

That was all Colorado could muster off Fiers (6-2), who got his first win in three tries against the Rockies. Fiers allowed just one run on seven hits, struck out four and didn't walk a batter

The A's broke the tie in the sixth inning. La Stella led off with a single and Matt Olson followed with a double to put runners on second and third. Matt Canha drove in La Stella with a groundout, and Olson scored on Lamb's single to make it 3-1.

Marquez (2-6) allowed three runs on six hits, struck out six and walked four in 6 2/3 innings. He is winless since beating the Giants on Aug. 4.