SAN FRANCISCO -- Five years had gone by since Homer Bailey's last start against the Giants. The lineup he faced Wednesday afternoon was largely different from his previous meeting against them, but Bailey picked up right where he left off.

In what was his most impressive outing since arriving to the A’s via trade last month, Bailey stymied the Giants over seven scoreless innings in a 9-5 victory that pulled Oakland within two games of the second American League Wild Card.

Bailey has been through ups and downs over his 13 big league seasons, but one constant has been his tormenting of the Giants. The 33-year-old entered the day 4-0 with a 3.57 ERA in eight career starts against San Francisco, tossing shutouts in two of those last three outings, including the second no-hitter of his career on July 2, 2013, as a member of the Reds.

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“It’s probably coincidence, but the atmosphere here is always great,” said Bailey, who owns a 1.20 ERA in his last five starts against the Giants. “It’s fun to play here. The weather is always nice and the fans really get into it. Everybody kind of has specific guys that they always seem to get out or teams they do well against; this one just happens to be one I do well against.”

In his short time with the A’s, the splitter has been Bailey’s make-or-break pitch. When it isn’t on point, as was the case in his outing against the Cubs last week in which he was rocked for seven runs over 4 2/3 innings, life becomes a lot more difficult for the right-hander. But when it’s working, like Wednesday when he threw it for 19 of his 91 pitches and generated five swing-and-misses, often using it to set up his seven strikeouts on the day, Bailey performs more like the talent he was projected to be after being selected seventh overall in the 2004 MLB Draft.

“From what we’ve seen, when his split is on, he’s a tough customer to deal with because he can throw it for strikes and get guys to chase,” A’s manager Bob Melvin said. “It keeps guys off his fastball and is tough to see.”

Giants catcher Stephen Vogt was one of the many batters to go hitless against Bailey, who surrendered just two. From his vantage point, it wasn’t just the splitter that made Bailey difficult, but the overall pitch mix, which made him tough to think along with.

"He was good. He didn’t really go over the heart of the plate. He was just off, just down, just up, just in,” Vogt said. “He was commanding four pitches today. Anytime a pitcher is doing that, they’re going to get some results. You tip your cap to him; he did a great job today."

With 2018 ace Sean Manaea likely one more rehab start away from returning to the Majors -- he’ll be pushed up to around 100 pitches in a start with Triple-A Las Vegas either Sunday or Monday -- one of the current members of the A’s rotation would likely have to be bumped out in order to make room.

After Wednesday’s dazzling start, Bailey certainly made a strong case to keep his role as a starter.

“I thought that was his best stuff of the year,” Melvin said. “He was able to throw his split in any count and got some swings and misses with it. Best we’ve seen him.”

Now the A’s begin a daunting nine-game homestand that starts Thursday with four games against the Astros, followed by three against the Yankees before ending with two against the Giants.

“I heard some people talking and saying all the teams ahead of us lost today. For us to pick up a win, especially after losing yesterday, is huge,” said third baseman Matt Chapman, who clubbed two homers in Wednesday’s victory. “If we have an opportunity to pick up a game, we need to.”