OAKLAND -- The A’s are getting pretty good at this extra-inning thing.

For the fifth time this season, the A’s took a game into extra innings. And for the fifth time, they came out on top as Mark Canha walked it off with a sacrifice fly in the 10th inning for a 5-4 victory over the Angels on Sunday at the Coliseum. The win increased Oakland’s lead atop the American League West standings to 4 1/2 games over second-place Houston, as it became the first team in the AL to reach 20 wins.

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Matt Chapman set the table for Canha with a single off Angels reliever Ty Buttrey that moved Franklin Barreto -- the A’s automatic runner at second base to begin the 10th -- over to third base.

“Chappy is looking for a good pitch to hit out over the plate to drive the other way and ends up pulling it. Mark is just terrific in those situations,” A’s manager Bob Melvin said. “He’s won us a couple of these games now with just staying inside the ball and hitting it in the air to right field.”

Canha found himself making adjustments during his at-bat against Buttrey. Noticing he was late on two 94 mph fastballs to fall behind in the count, 0-2, Canha decided to spread out his feet a bit more in the box and shorten up his swing. Getting the fastball again on a 1-2 count, Canha connected for the game-winning sac fly.

“I always believe in myself in these situations,” Canha said. “Just take a good approach up there and win this game. Sometimes it works, and sometimes it doesn’t.”

There may not have been a player the A’s would rather have up in that situation than Canha. Entering Sunday, the A’s outfielder/DH was batting .393 (11-for-28) with a 1.110 OPS in the seventh inning or later.

“He’s really confident and calm. He understands the situation. He thinks really clearly up there,” Melvin said. “Some guys tend to speed up. He knows exactly what he needs to do. In that at-bat, that’s all he was trying to do. He doesn’t let the frustration of other at-bats carry over.”

Struggling to find success without hitting homers, Sunday’s win was the A’s first this season in which they didn't go deep. They had lost their previous five homerless games.

The A’s traded in the long ball for small ball, driving in four of their five runs with either a single or sacrifice fly. Canha’s walk-off sac fly completed a comeback that began in the sixth, when Oakland strung together a two-out rally with four consecutive hits, capped by Sean Murphy’s chopping RBI single up the middle that reached the outfield to tie the game at 4.

“He was trying not to do too much and stay in the middle of the field, where most of the holes are,” Melvin said. “He found a hole. He didn’t crush it, but did just enough. All of a sudden, it was a different ballgame and a different mindset for us in the dugout.”

The A's bullpen also played a large role in the comeback, as they shut down the Angels over the final five innings after starter Frankie Montas departed with two outs in the fifth and trailing, 4-2. Yusmeiro Petit and T.J. McFarland were unavailable due to heavy workloads the past few games, so Melvin relied on J.B. Wendelken, Jake Diekman and Joakim Soria before going to closer Liam Hendriks in the 10th.

Hendriks set up Oakland for its fourth walk-off win of the season with a perfect top of the 10th, stranding automatic runner Jo Adell at second to keep the game tied.

A’s relievers have not allowed a run in their past 17 innings after combining for 5 1/3 scoreless frames on Sunday.

“I've got to give a shoutout to the bullpen, because they keep shutting the door with that new extra-inning rule,” Canha said. “When you do that, it’s huge. Going into the bottom half just having to score one takes pressure off the offense and makes the job a little bit easier.”

Winners of 10 of their past 11 home games, the A’s now embark on a 10-game, three-city road trip that starts on Monday at Texas and continues through Houston and Seattle.

“Three different road series in a row is going to be a challenge,” Canha said. “Houston is always tough, and Texas is no slouch. Even though we’re feeling good right now, we have to buckle down and keep piling up the wins.”