ANAHEIM, Calif. (AP) -- The Los Angeles Angels had just won the opener of a pivotal three-game series against the team they're chasing in the AL West, yet manager Mike Scioscia was still fuming about a replay reversal that took a home run away from Mike Trout.
The Angels pulled within 3 1/2 games of the A's in the division.
Oakland manager Bob Melvin challenged first base umpire Bob Davidson's home run call on Trout's towering drive to right field in the fifth inning, believing the ball was touched by a fan at the top of the 18-foot wall. After the call was overturned, Scioscia came out to argue and was ejected by Davidson.
''I don't know how they overturned the home run. That ball was over the yellow line when it hit that guy's glove. There's no doubt,'' Scioscia said. ''I don't know what they saw in New York - and that's part of the frustration that I have with this whole system. There's no way that's indisputable evidence that that was not a home run.''
Trout was running too hard to notice what happened.
''I really didn't think I got enough of it to go out. I was thinking three bases the whole time,'' he said. ''Running around second, I thought it hit high off the wall so I just put my head down and was busting it to third.''
Trout's only hit of the game drove in Hank Conger, who had bunted his way on and continued to second on the first of three throwing errors by third baseman Josh Donaldson - two of which led to unearned runs.
''It's just one of those things where it just kept building,'' Donaldson said.
Richards (6-2) allowed a run and four hits, struck out four and walked none. The right-hander, who pitched four-hit ball through eight innings last Wednesday in a 4-0 win at Houston, gave up just two harmless singles over his final 5 1-3 innings against an offense that came in leading the majors in runs and on-base percentage.
The last time Richards faced the A's on May 30, he gave up five runs and got only two outs. He entered Monday 0-3 with a 7.50 ERA in his six previous career starts against the A's.
''I wasn't really thinking about it too much,'' Richards said. ''But in the back of your mind, you want to do better than you did. ... I felt like this time was my turn to come out and show them what I've got.''
Joe Smith pitched a perfect eighth inning and Ernesto Frieri struck out the side in the ninth for his 11th save.
Jesse Chavez (5-4) allowed three runs - two earned - and eight hits in six innings with five strikeouts. It was the ninth time in his 13 starts this season that he yielded fewer than three earned runs, but his record in those games is only 4-2.
The Angels, coming off sweep of the Chicago White Sox, were out to avenge a three-game sweep by the Athletics 1 1/2 weeks earlier at Oakland. They broke a 1-all tie in the fourth with a bloop RBI single by Raul Ibanez. Ibanez's hit drove in David Freese, who drew a leadoff walk after walking all four times up in Sunday's game.
Stephen Vogt and Yoenis Cespedes each had two hits against Richards. Vogt opened the scoring in the second inning with a two-out RBI single after a double by Cespedes.
Chavez hit Conger on the right elbow with his first pitch of the third, after Richards plunked John Jaso on the left foot with two out and the bases empty in the top half.
Conger hustled to third on Kole Calhoun's bloop single to left-center and scored the tying run on a sacrifice fly by Trout, who was robbed of extra bases on a leaping catch by center fielder Coco Crisp a few feet in front of the fence. Conger added an RBI single in the eighth against Jim Johnson.
Scioscia said before the game that Tuesday night's scheduled starter, Tyler Skaggs, will go on the 15-day disabled list because of a right hamstring strain. Hector Santiago was expected to be recalled from Triple-A Salt Lake to make the start.
NOTES: Scioscia's ejection was his first this season and 37th since becoming Angels manager in 2000. ... The Athletics' failed to hit a home run after getting at least one in each of their previous 16 games (27 total). ... Richards' next start will be in Atlanta next weekend. He has allowed no more than two runs or five hits in any of his six road starts this season. ... Oakland 1B Alberto Callaspo, whom the A's acquired from the Angels in July 2013, was 0 for 3 is hitless in 13 career at-bats against Richards.