Olson hit two home runs, Fiers remained unbeaten in his last 10 starts and Oakland defeated the Los Angeles Angels 7-2 Friday night.
It was Olson's first multihomer game this season and the fifth of his career. The first baseman -- who also had three hits and tied a career high with five RBI- is 7 for 15 on the Athletics' current road trip.
"I am in a stretch where I am not fouling off or swinging through the pitches I should be putting in play. I'm just trying to keep it rolling," said Olson, who has hit nine of his 16 homers in the last 23 games.
Olson had Oakland's first hit with a two-run shot to right-center in the first inning off Noe Ramirez (3-1) and added a three-run blast to right in the third.
Olson missed five weeks earlier this season after breaking the hamate bone in his right hand. Manager Bob Melvin said that Olson has been consistent since returning to the lineup.
"He is seeing the ball pretty well," Melvin said. "It's not just fastballs. He is hitting breaking balls and sits on pitches at times."
Fiers (8-3) allowed a run and six hits over 6 2/3 innings. The right-hander is 6-0 with a 2.38 ERA since May 7 against Cincinnati, when he threw his second no-hitter.
He allowed the Angels' leadoff hitter to get on base three of the first five innings, but they weren't able to advance into scoring position.
"I was a little wild but effectively wild," Fiers said. "I was missing my spots early on but guys were making good plays behind me. After that I settled in and felt a lot better"
Mark Canha accounted for Oakland's other runs with his 11th homer of the season, a two-run shot to left in the seventh inning.
Ramirez was used as an opener for the third time this season and gave up a run for the first time. He had allowed three hits and struck out four over 3 1/3 innings the previous two times he started.
The Angels have used an opener 15 times this season with six different relievers. They have gone to an opener in front of Felix Pena in 10 of his last 11 appearances.
Pena allowed only two hits in five innings, but one of them was Olson's three-run shot. The right-hander struck out seven.
"I thought we pitched well but the home runs were costly. If you take Olsen and Fiers out of there we had a pretty good game," Angels manager Brad Ausmus said.
STREAKS AND STATS
The Athletics have hit 80 home runs since May 13, which is tied with the Twins for most in the majors over that span. ... Angels 2B Tommy La Stella -- who had a pair of singles -- has 82 hits on the season, which is a new single-season career high. His previous best was 80 with Atlanta in 2014. ... Pujols is one hit shy of tying Tony Gwynn (3,141) for 19th on the career list.
Athletics: DH Khris Davis was out of the lineup after being hit on the hand by a pitch during Thursday's game. Melvin said Davis' left hand is still swollen and that he is having trouble gripping the bat.
Angels: C Kevan Smith (left hand metacarpal sprain) will take some swings tomorrow for the first time since going on the injured list June 20.
Athletics: LHP Brett Anderson (7-5, 4.26 ERA) is averaging 4.57 strikeouts per nine innings, which is the lowest mark in the majors.
Angels: LHP Tyler Skaggs (7-6, 4.30 ERA) is looking to become the first LA pitcher to win four straight starts since Hector Santiago won his final six three years ago.
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