SAN FRANCISCO -- Kris Bubic admitted his adrenaline was flowing more than usual when he took the mound in the bottom of the first inning Tuesday night at Oracle Park.

Pitching against the team you grew up rooting for, at the ballpark where you grew up going to games, with 30-40 friends and family in the stands there to support you will do that.

But Bubic, who went to high school in San Jose, about 45 miles south of Oracle Park, was able to corral that emotion into a solid start in the Royals’ eventual 4-2 defeat to the Giants. Kansas City has lost four in a row ahead of Wednesday’s series finale.

“I was a Giants fan growing up. I know Royals fans in 2014 probably don’t want to hear that,” said Bubic. “But just being from here, this is the team I grew up watching, the park I grew up coming to, so it was pretty cool to be out there.

“When I was warming up pregame, [I was] just trying to take it in a little bit because us being in the AL Central, we don’t come out here often. I’ve never been on the field as a player. So it’s pretty special.”

And Bubic put on a show for five innings Tuesday. He had a no-hitter going through 4 1/3 innings and had allowed just one hit entering the sixth. He struck out a season-hgh six batters and was mixing well with his arsenal, running his fastball up to 96 mph, using his changeup in key spots and flashing a much-improved feel for his curveball, which generated two whiffs on five swings and two called strikes.

“I’d be lying to you if I told you I wasn’t trying to throw harder tonight,” Bubic said. “But I think just a combination of better intent and better fluidity in my delivery. …

“You feed off your confidence, especially early on. Once you get into a good rhythm early on, then you just try to keep that as consistent as you can. That was probably the best the stuff’s been all year, and probably the best I’ve thrown over a whole outing all year.”

Bubic was on pace for a quality start, but things fell off track when four out of his five hits allowed came in the sixth.

“It was one of those in the makings of being a very, very special start,” manager Mike Matheny added. “Unfortunately in the sixth, infield hit, a ball found the outfield grass that normally doesn’t. Took it away from him.”

The sixth and final strikeout came in that sixth frame, when Bubic got Austin Slater swinging on a fastball for Slater’s third strikeout of the night, all on different pitches. That was the start of the third time through the order for Bubic -- and his last out of the evening.

With a man on second base and one out, Wilmer Flores broke the scoreless tie with an RBI single. Bubic had the third baseman at two strikes before leaving a changeup over the middle of the plate.

“We were throwing him a lot of fastballs to get to two strikes, he was fouling them off,” Bubic said. “And then 3-2, it’s frustrating with a base open and a lefty on deck, it’s probably not a pitch or location you want to throw.”

Joc Pederson, the lefty on deck, reached on an infield hit. Darin Ruf’s RBI single made it 2-0 and knocked Bubic out of the game, and he was charged with three runs in 5 1/3 innings after Tommy La Stella hit a sacrifice fly off reliever Dylan Coleman.

The Royals’ pitching has faced a slew of issues this season, and one of the big ones has been how their starters fare against an opposing lineup the third time through the order. Entering Tuesday, Royals starters had allowed an .846 OPS facing an opponent for the third time, the fifth-worst such figure in the Majors.

Their 1.686 WHIP is second-worst, and their .320 batting average against is fifth-worst.

Hitters will inevitably look more comfortable against pitchers the more they see them, but the Royals are running into that issue more than most. Matheny wasn’t going to pull Bubic after five innings, as he was still dominating at that point. Even after allowing two runs, there was a thought to let Bubic keep rolling.

But with the game close and the Royals offense held scoreless by Giants starter Logan Webb for what would be seven strong innings, Matheny turned to the bullpen.

“That infield single just put us in a spot,” Matheny said. “Really liked how he was still throwing the ball. He still looked strong. That’s his game at that point. We want him to take it. Three [runs] got to be too many, especially when their starter was stingy. … [Bubic] had enough stuff to roll for a while.”