Afterward, manager Ned Yost seemed to have a ready-made analogy to describe his long-locked pitcher.
"It's kind of like his hair," Yost said. "His streak gets a little bit longer and little bit fluffier as time goes on.
"What he's doing is he's attacking the strike zone with good natural movement on the fastball, which is tough to center. And he's being very effective with his curveball and his changeup. You add all that up and he gets quick outs, he goes deep into games and I think we're seeing a lot of what they saw last year in the Pacific Coast League, which is why he was the Pacific Coast League Player of the Year."
White Sox starter Chris Sale was also pitching well, and the game was deadlocked, 2-2, in the seventh inning. That's when Perez came through with some offensive heroics.
With one out and runners at the corners, Alcides Escobar stole second base on an Alex Gordon strikeout. Chicago then intentionally walked Billy Butler to load the bases and bring up Perez.
"Billy is a guy you want to stay away from and you take your chances with Perez," said White Sox manager Robin Ventura.
Perez made them pay, smacking a tie-breaking two-run double off the left-field wall, his second two-bagger of the night.
"I hit it good, but I thought it'd be maybe a double," Perez said. "When he kept running back to the fence, I said 'Thank you!'"
"Clutch hitting by Salvador Perez," Yost said. "It was set up with a nice hit-and-run by Escobar to put us in that position and Esky moving up on Gordon's strikeout. They walked Billy and Sal hit a pretty darn good pitch, raked it off the ground just about to put it off the left-field wall.
"We've said all along, that's the reason we signed Salvy to a long-term contract. We think he's going to be special."
Perez's double was the key hit after Butler and Lorenzo Cain each tallied a solo home run off Sale. Butler's homer tied the game, 2-2, and afterwards, the man referred to as "Country Breakfast" said the blast gave his team the jolt it needed.
"I definitely hit that one real good. I didn't miss it. Fastball over the plate and I got it and got underneath it," Butler said of his 25th home run. "I was real happy to give our team some confidence there, get the game back tied. ... I think that definitely gave us a big boost and put our confidence a lot higher going into the next inning."
Sale has been a thorn in the Royals' side this season. They defeated him on May 12, but he's emerged victorious in each of his last two starts. This time, the Royals got the win over the All-Star.
"He's got great stuff, and he's pitched well all season," Butler said. "He's given us fits. We just kind of waited him out and kept battling and pulled through late on him."
But back to Mendoza. Yost was on to something when he described Mendoza's streak as longer each time out. The right-hander hasn't allowed more than four runs in a start since April, and since June 29, he's won five games and posted a 3.58 ERA.
"I just try to, every outing, pitch the same. And if I get a good outing like this one, it makes me more confident in my next start," Mendoza said. "I feel better. Every start, I just kind of feel stronger."
"He's strung quite a few starts together that have been real good," Butler said. "He's the best pitcher on our staff right now with the stuff that he's been throwing by far. He's been going out there and going deep into the game every time out."
It hasn't just been Mendoza, though. The Royals rotation has been on fire of late. On the current homestand, Jeremy Guthire, Will Smith, Luke Hochevar and Mendoza have combined to allow just seven runs in 28 innings.
"I see my teammates do well, and I want to do the same thing," Mendoza said.
"We said it all along from the beginning of the year on," Yost said, "if we get good starting pitching, we feel like we've got a chance to compete every single night. And that's been the case."
A win over the AL Central-leading White Sox is certainly something to smile about, but it wasn't all good news for the Royals. Second baseman Chris Getz took a pitch off the left thumb while attempting to lay down a bunt in the fifth inning. After having X-rays at the ballpark, it was determined that Getz had a fracture in his thumb. He's slated to have surgery Saturday and will miss the remainder of the season.
"It's very unfortunate," Butler said. "Getzy's a great teammate, he's a great player, he's a great second baseman for us. He's been playing really well this year, and he's just been hit by the injury bug. I feel real bad for him that the season ended that way for him."