SAN DIEGO – Strike three blew by Jake Cronenworth too fast for most to register, and all the Padres first baseman could do was watch it land hard in Royals catcher Freddy Fermin’s glove before walking back to the Padres dugout.

The 103.8 mph fastball from Royals reliever Aroldis Chapman was the fastest pitch in Royals history and matched Jordan Hicks for the fastest pitch in MLB this year.

It also couldn’t have come in a bigger spot, with the Royals hanging on by a run against this vaunted Padres lineup.

• Game Story: Royals put up a 5-spot in second inning ▶️

Kansas City’s bullpen locked down a 5-4 victory Tuesday night at Petco Park. Three high-leverage relievers were nails in an otherwise sloppy game from both teams, and the Royals, too often on the losing side of the razor-thin margins this sport offers, evened the series before the finale Wednesday afternoon.

“That’s a great win against a team like the Padres,” Royals captain Salvador Perez said.

A day after the Royals were held to two hits, they jumped out to a five-run lead off Padres starter Seth Lugo, sending nine batters to the plate in the second inning. Perez’s two-run double proved to be the game-winner -- but the Royals didn’t help themselves much as the game continued.

Two errors, a missed catch in foul territory and a poorly timed dive helped the Padres cut their deficit to one against Royals starter Brady Singer, who allowed four runs (two earned) in six innings.

With two outs in the fifth inning, Padres catcher and No. 9 hitter Brett Sullivan hit a popup in foul territory down the third-base line. Left fielder Edward Olivares and third baseman Maikel Garcia convened, but no one called for the ball, watching it drop.

"That’s a play that needs to be made,” manager Matt Quatraro said. “They’re aware of that. They understand it. … I don’t really know what exactly happened. We’ll talk about it after, but that play needs to be made.”

Errors from right fielder MJ Melendez and second baseman Matt Duffy followed before the inning was done. Singer needed 13 extra pitches after Sullivan’s pop foul dropped.

“I still think I could have done a better job,” Singer said. “Those things are going to happen. You’ve got to be able to make pitches there and pick them up. … I’ve got to learn to overcome that and make some better pitches.”

The Royals’ bullpen executed its pitches, and it started with Chapman in the seventh inning. The former All-Star closer has pitched the ninth inning in 520 games in his career and made 101 appearances in the eighth. Before Tuesday, just 43 of his appearances had come in the seventh.

“Before, I knew when I was going to pitch,” Chapman said through interpreter Luis Perez. “Now, I just have to be ready after the sixth inning and know that I might come in.”

When the Royals signed Chapman to a one-year deal this offseason, they did not promise him the closer role, saying he had to earn it after a career-worst season last year. He has regained his form, but the Royals have used him more as a setup man for Scott Barlow, who notched his fifth save Tuesday.

The Royals wanted Chapman for the top of the Padres’ lineup in the seventh.

“His selflessness to say, ‘I’ll pitch whenever,’ the fact that he’s willing to do that, lets us set up what we think are our better matchups throughout the later innings,” Quatraro said.

Chapman walked pinch-hitter Nelson Cruz, who was lifted for pinch-runner Adam Engel. Almost two weeks ago, Baltimore took advantage of Chapman’s slow time to the plate and stole four bases off him. On Tuesday, Chapman made a pickoff attempt to keep Engel at first and then caught him stealing, throwing over to first baseman Vinnie Pasquantino, who threw to Bobby Witt Jr. for the out.

Chapman froze Cronenworth with that 103.8 mph pitch to end the seventh and turned the eighth over to Taylor Clarke, who executed his own pickoff move, erasing Rougned Odor with the tying run on third to end the inning.

“I should've stayed closer to not get out,” Odor said. “But he had a really quick move, and he got me when I was going to do another step. So that's why I didn't even have time to slide back. I was trying to do another step and that was when he picked.”