SAN FRANCISCO -- When Kris Bubic pitched at Oracle Park last season, he admitted he was starstruck pitching at the ballpark where he grew up going to games. Since he got that feeling out of the way last year, when he took the mound Sunday, he could just focus on pitching.

And he spun a gem. Bubic threw six scoreless innings against the Giants in the Royals’ 3-1 loss on Sunday afternoon, allowing just two hits and punching out nine, matching his career high.

“He was incredible,” interim manager Paul Hoover said. “He gave us what we were hoping for, and that was six innings. … He was great. Couldn’t have asked for anything more."

The Royals were seven outs away from sweeping the series until the bullpen plan fell apart. Bubic exited after six innings, 76 pitches and with a 1-0 lead, and righty Carlos Hernandez came in for the seventh. But he felt a cramp on the pitch that Brandon Crawford popped up for the second out, thus setting in motion pitching confusion.

Giants manager Gabe Kapler had Blake Sabol ready to pinch-hit against Hernandez, a move announced over the PA system. So Hoover signaled for lefty Ryan Yarbrough from the bullpen. But home-plate umpire Dan Iassogna had not officially subbed in Sabol yet, so Hoover brought Hernandez, who threw injury warmup pitches, back on the mound.

When Sabol was officially signaled into the game, the Royals went to Yarbrough. Hernandez said he was “all good” after the game, so it was unclear whether he left with an injury.

“That’s my fault,” Hoover said. “When I went out there, we were making that move, and Dan came to me and told me that he didn’t put [Sabol] in the game yet. So Carlos came back out until they made the move, and then we went to Yarbs.”

Yarbrough struck out Sabol looking to end the inning, but the damage came against the lefty in the eighth. Bryce Johnson singled and scored from first on Wilmer Flores’ double, with left fielder Nate Eaton making it a close play at the plate but perhaps rushing the offline throw home. The Royals had the matchup they wanted with Yarbrough against lefty Michael Conforto; closer Scott Barlow was not yet warming up in the bullpen because the Royals didn’t want to push him for four outs this early in the season.

But Yarbrough left a breaking ball up, and Conforto crushed it for a two-run game-winning homer.

“From the two days I’ve thrown against them, the pitch to put guys away was the breaking ball,” Yarbrough said. “I was trying to make a good pitch, I left it up enough where he could get to it and he did some damage with it.

“For me to let them down like that, it’s a tough way to end. It leaves a bad taste in your mouth.”

The Royals still left San Francisco with a series win. And with such an emphasis on young starters taking a step forward in 2023, Bubic’s gem won’t be ignored.

The lefty didn’t allow a hit until the fifth, mixed all four of his pitches well and registered weak contact throughout his six innings. His fastball velocity is up, and he registered a career-high 18 whiffs on 41 swings (45%).

“That’s, in my eyes, the most satisfying [part] for me because that’s been the work in progress,” Bubic said. “The whiffs haven’t been there in the past. To get those bad swings against lefties and even some righties, it’s encouraging."

Bubic said he “got creative” on the shape of his slider Sunday after seeing the movement in his season debut. It had more sweeping movement to lefties, like when he struck out Crawford swinging in the fifth (despite it registering as a curveball). Bubic kept the slider tighter to righties, such as Austin Wynns’ swinging strikeout to end the second.

“To lefties, I’m OK with the velo dipping, getting some more sweep,” Bubic said. “It’s not as consistent as I want so far. To righties… it’s a tighter, harder shape. If I can just keep the separation between that and the curveball, I think it’ll be fine with the way the fastball and changeup could play."

The Royals want to see their starting pitching improve this season under first-year pitching coach Brian Sweeney. Through 10 games, Royals starters rank fourth in baseball with a 3.29 ERA.

“We’re starting to turn the corner,” Bubic said. “Our pitching staff’s been really good so far. The offense is getting timelier and timelier each game. There will be days when we pick them up, and there will be days when they pick us up."