"For me the big play of the game was Gio, by far. I'll be honest, our dugout was dead. We hadn't gotten close to [White Sox starter Philip] Humber," Royals outfielder Jeff Francoeur said. "Gio put together a huge at-bat against a guy who's not easy to hit. I thought that kind of livened us up and we were able to relax and have some good swings."
Five different pitchers combined to preserve the win for Mendoza (2-2), who scattered seven hits and struck out five in a season-high workload.
Mendoza's lone blemish came in the third, when Paul Konerko's single to left scored Brent Lillibridge, who led off the inning with a walk.
Aside from that, the right-hander got out of a two-on, one-out jam in the third with an inning-ending double play grounder off the bat of Alex Rios and, with runners on second and third with two out in the fourth, got Lillibridge to ground back to the mound.
"Mendoza, he did a pretty good job," White Sox manager Robin Ventura said. "He came into the game without knowing that he was going to pitch so many innings, and he stopped us, and that was impressive. He just did an awesome job."
"I can't imagine what those guys do. As a position player every once in awhile you might get thrown in to pinch-hit or pinch-run, but as a pitcher, when you're down there in your mindset you're not ready for a game like that," Francoeur said. "That was unbelievable what he came in and did."
Duffy, who it was announced after the game will return to Kansas City and undergo an MRI on Monday, was happy the bullpen bailed him out after he was unable to go.
"I'm pumped to see my boys pull through today," Duffy said. "It would've been a real tough day if they didn't and they did and it was awesome."
Konerko's third-inning RBI appeared to be all the White Sox would need, as Humber turned in his best outing since last month's perfect game. The Royals put more than one runner on base only once -- in the fifth -- as the right-hander evaded trouble until being lifted in the seventh with two outs and Alcides Escobar on second.
Thornton, who took the loss, entered and walked Jarrod Dyson before Giavotella's pinch-hit double to right scored Escobar and Dyson.
Humber received a no-decision despite holding the Royals to four hits and striking out seven in 6 2/3 innings.
Humber's performance was quickly forgotten thanks to a rough ninth inning in which the Royals tacked on six runs against Addison Reed and Eric Stults. Reed allowed six runs on two hits and three walks (two intentional) while getting only one out. Stults entered with the bases loaded and allowed two more runs to score before getting an inning-ending groundout.
All six runs were charged to Reed, who entered with 13 consecutive scoreless appearances, a White Sox rookie record.
Francoeur also hit his first home run of the season in the eighth inning, a solo shot off Nate Jones.
"You can say all you want about how you try to relax, but it felt like a weight was lifted off my shoulders," Francoeur said. "I'd sit here and lie if I didn't tell you that."
It also was a relief for the Royals to post a comeback win after receiving an early blow.
"It was good to come in here and win two out of three, that was big for us," Royals manager Ned Yost said. "But the way the game was going, Humber was really doing a good job of hitting his spots early, [he had a] really good curveball, and it didn't feel like it was going to be a 9-1 game."