ANAHEIM -- It was the kind of game the Angels have been losing all season, especially during a recent skid that had seen them lose nine of their last 12 games.

But the Angels overcame an early four-run deficit and won a close game keyed by a three-run seventh inning and a go-ahead sacrifice fly from Justin Upton in the eighth in a 6-5 win over the A's in Sunday’s series finale at Angel Stadium. Angels manager Joe Maddon believed it was an important victory for the club’s collective confidence, especially the relievers.

"We have to beat these teams in our division and we have to know that and they have to know that, too," Maddon said. "It starts right there. The bullpen has been much maligned but they did a great job. The only thing we need to get going with this group is their confidence. They are good. They're very talented, they just don't have that mojo, that confidence. But [they] will."

After seeing the bullpen struggle of late, especially in losses to Oakland on Friday and Saturday, Angels relievers came through in a big way after right-hander Dylan Bundy lasted just 2 1/3 innings in his third straight shaky outing. Aaron Slegers threw a scoreless frame, Steve Cishek turned in 2 1/3 shutout innings, Mike Mayers threw 1 1/3 scoreless innings and Raisel Iglesias had a four-out appearance, earning the victory after the Angels went ahead for good in the eighth.

The only blemish was lefty Tony Watson failing to protect a one-run lead in the eighth after the Angels took the lead in the seventh. Watson was hit by a comebacker with two outs and threw the ball away at first base, allowing the game-tying run to score.

“Tony was a little bit off today, but I have a lot of confidence in Tony,” Maddon said. “The ball off his glove could've been an out. It's just the way things fly."

But the Angels retook the lead in the eighth, as Taylor Ward drew a leadoff walk, advanced to second on a sacrifice bunt from Kurt Suzuki, reached third on a single from David Fletcher and scored on Upton's sacrifice fly to left field.

Upton said he was just trying to hit something in the air and was pleased to contribute to a win in his first-ever start at leadoff hitter in 1,778 career games.

"I know from the outside it doesn't look the greatest, but these guys are fighting every single day," Upton said. "We as a team, we feel like sometimes we're putting ourselves in positions [to win], but it just hasn't worked out for us. But we battled back today and put ourselves in position to win one and we were able to. Hopefully this can spark the club."

Iglesias, who recorded the final out in the eighth, came back out for the ninth and breezed through the frame, earning his third win of the season.

It was a positive sign after the right-hander gave up two homers on Friday.

"They came in and they got outs for us," Upton said of the bullpen. "Even Tony, he almost got himself out of a situation but made an unfortunate error. And then Iggy came in and closed out. That's all we can ask for from those guys and they did a great job."

The late-inning magic likely wouldn't have been possible without Jared Walsh getting the Angels back in the game with a solo shot in the sixth, his 10th homer of the year.

Fletcher also sparked a three-run rally in the seventh with a one-out walk, with Upton following with a single. Pinch-hitter Jose Rojas hit a hard grounder just past second baseman Tony Kemp for an RBI single and Anthony Rendon walked to load the bases.

It set the stage for two-way star Shohei Ohtani to pinch-hit on his scheduled day off, and he delivered with a game-tying sacrifice fly to right field on a line drive that had an exit velocity of 110.9 mph. José Iglesias followed with an RBI single to give the Angels their first lead of the game to that point.

It helped the Angels snap their three-game losing streak, giving the Halos an opportunity to build off a game that saw several key players contribute against the first-place A’s.

"It had a lot of drama, a lot of good stuff," Maddon said. "Walshy had great at-bats. He hit two bullets right at them and then one over the wall. Suzuki had a great bunt. I could go on and on. It was just a lot of good things and a lot of the little things done well. That's the kind of game I want us to play."