OAKLAND -- Sean Manaea has flashed brilliance through stretches of his six-year big league career, but nothing prolonged enough to earn him a spot on an All-Star team. He seems to be building a strong case for an appearance in this year’s Midsummer Classic.

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Following a shutout in his last start, Manaea made it two consecutive outings in which he has held the opposition scoreless by blanking the D-backs over six innings in the A’s 4-0 win at the Oakland Coliseum on Wednesday afternoon. With no runs allowed over his past 15 innings, the left-hander’s ERA now ranks seventh lowest in the American League at 3.09.

Though Manaea allowed only two hits and two walks Wednesday, he wasn’t quite as efficient as in his four-hitter in Seattle on June 2. In fact, there was concern he might be in for a short day after he labored through the first two innings on 50 pitches as Arizona’s hitters consistently put together long at-bats with a flurry of foul balls in two-strike counts.

“When I hit 50 pitches, I sat down and kind of evaluated the situation,” Manaea said. “I’ve got 50 or so pitches left to work with, so let’s just try to be as efficient as possible.”

Making a concerted effort to pitch more aggressively to contact, Manaea threw just 13 pitches each inning from the third through the fifth. He retired 10 in a row at one point and capped off his start by retiring 13 of his final 15 batters to finish with a season-high-tying 111 pitches. With only three strikeouts recorded, he relied heavily on his defense. Of the 18 balls put in play against Manaea, D-backs hitters averaged an exit velocity of just 82.2 mph.

Most of that weak contact came against Manaea’s sinking fastball, a pitch he threw 62 percent of the time. The changeup was also there to help him when he fell behind in the count.

“He’s doing a really good job of commanding the fastball and throwing that changeup off of it,” A’s center fielder Mark Canha said. “Over the course of his career, I’ve noticed he’s gotten so much better at spotting up and hitting both sides of the plate. Fastball command is everything, and he’s doing a really good job of that.”

Manaea was supplied an early lead with three runs in the second inning. After Elvis Andrus drew a walk to put runners at first and second with two outs, Canha drilled a ball 102.1 mph off the bat that appeared to be caught on the run by Ketel Marte to keep the game scoreless. However, the ball popped out of Marte’s glove after he slammed into the wall in left-center field, causing a brief moment of confusion as to whether the play was ruled an out.

Canha, who removed his helmet after watching the ball sail into Marte’s glove, immediately put it back on once he saw the ball rolling on the warning track, and he raced to third base. Upon the umpires’ review of the play, Canha was allowed to remain on third with a go-ahead two-run triple. He scored one batter later on an infield single by Jed Lowrie.

"I was getting ready to spike my helmet on the ground,” Canha said. “I felt like that [ball] should have gone out. I just saw the ball on the ground and just ran. Tried to act like I saw him drop it and make it seem like the ball was not caught. It was a crazy play. I had no idea when it went to replay what they were going to do. Just glad it worked out."

Winners of six of their past seven games, the A’s are a season-high 11 games above .500 (37-26) as they maintain sole possession of first place in the AL West. Though home runs have been Oakland's calling card for much of the season, its recent stretch of success has been the result of stellar work from its starting pitching.

Over the past seven games, A’s starters are 5-1 with a 2.57 ERA.

Manaea has allowed one run or none in each of his past four starts, with an ERA of 0.68 over that stretch.

“The pitchers have been running the show,” Canha said. “They’re the ones carrying us right now, and we’re doing just enough on the offensive [side] to get a few wins. It’s a good recipe when the pitching has been as good as it is. You’re giving yourself a good chance every night.”