Diamond turned in arguably his worst start of the year, giving up a season-high six runs on seven hits and a walk over 5 1/3 innings. It's been a tough few weeks for Diamond, as since being ejected for throwing near Josh Hamilton's head on Aug. 23, the rookie has a 7.33 ERA in four starts.
He's now thrown 188 1/3 innings this year, including 34 2/3 innings in the Minors, which tops his career high in innings pitched from last year, when he tossed 162 innings between Triple-A and the Majors.
"You end up playing an extra month when you get to the big leagues like this, and that means something because innings start going up," Twins manager Ron Gardenhire said. "But I thought his pitches today were more crisp than the last time, and he had some pretty sharp pitches. I thought his changeup was better, his slider was a little bit better than the last time.
"I was worried that he was getting into that dead-arm stage, but he said he felt better and felt good, and that he felt like he made some strides."
Diamond, who fell to 11-8 with a 3.69 ERA in 24 starts, added he doesn't feel tired despite the heavier workload.
"Physically, I feel fine," Diamond said. "I still feel like the ball is coming out well. I was able to work down today even though I gave up a lot of fly balls. But I'm trying to go as deep into games as I can, but right now I can't get into the seventh-inning mark, which is usually my goal."
The White Sox scored twice in the third -- coming on a sacrifice fly from Dewayne Wise and an RBI double from Kevin Youkilis -- before scoring again in the fourth on an RBI double from Dayan Viciedo.
Chicago broke it open with a six-run sixth inning that featured plenty of power from White Sox hitters. Diamond served up a leadoff homer to Adam Dunn before giving up a two-run homer to Viciedo after Alex Rios tripled.
"It was big to get some runs," White Sox manager Robin Ventura said. "Home runs are good, but I like the ones where we just push a couple across here and there."
Viciedo's homer knocked Diamond from the game, but reliever Anthony Swarzak didn't fare much better. Alexei Ramirez quickly reached on a fielding error by shortstop Pedro Florimon before Swarzak walked the next two batters to load the bases.
Wise came through with his second sacrifice fly of the game before Youkilis laced an RBI single. That was it for Swarzak, who was replaced by Kyle Waldrop, who promptly gave up an RBI single to Dunn.
It was more than enough support for Jake Peavy, who was solid for the White Sox. The right-hander surrendered just two runs on four hits and a walk over six frames while striking out six.
The Twins actually got on the board first with a solo shot from Joe Mauer in the first inning. It was Mauer's 10th of the year and came in his first at-bat after missing five games with back spasms.
Minnesota made it a one-run game in the fifth, when Alexi Casilla roped on an RBI double to score Trevor Plouffe after he doubled to lead off the inning.
But it was as close as the Twins would get, as the White Sox turned the game into a blowout in the sixth. The win gave the first-place White Sox a three-game sweep over the Twins, as Minnesota has lost nine straight series to Chicago.
"A tough series against a team over there that's playing pretty good baseball," Gardenhire said. "They're not making mistakes, and they're killing you when you make one."