Harden won his fourth straight decision and posted his fifth double-digit strikeout game since joining the team. He has fanned 11 once before, doing so June 26 against Philadelphia while with the Athletics.
The only blemish in his seven innings was a leadoff homer in the third by Austin Kearns, when a pitch he wanted out came in. Harden gave up two hits and did not walk a batter, and now has given up one run over his last 19 innings.
"He gives you a chance every time he goes out there," Cubs manager Lou Piniella said of the right-hander, who took advantage of the cool, Northern California-type weather at Wrigley Field.
Harden is 9-2 against National League teams, and has given up 19 earned runs in 103 2/3 innings. He's struck out 70 in 49 innings in his eight starts with the Cubs.
"I have to give a lot of credit to Soto," Harden said of the young catcher. "We've been working really well together. I think it comes down to mixing up pitches and keeping the hitters off balance, keeping them guessing, and he's done a great job of that."
DeRosa has faced Harden, and knows exactly what hitters are discovering -- you can't outsmart him.
"He's got that extra notch," DeRosa said. "He sits there at 91, 93 [mph], and when he needs it, he can get it up to 97. When I faced him, the thing I noticed was that his arm action on every pitch is identical. You have to respect a guy who throws 95 miles an hour, and is throwing a changeup that looks like a knuckle split at 83 [mph], but it's the same arm action coming at you. You're going to see some good hitters look bad against a guy like that."
Kosuke Fukudome hasn't been looking too good at the plate, but a morning pep talk from Piniella and some extra work in the cage resulted in a two-run pinch-hit homer in the seventh, ending an 0-for-10 skid.
With the win, the Cubs are 15-6 in August, and have won at least 15 games each month for the first time since 1969. They are the first National League team to reach 80 victories this season. That's a lot of firsts. And they did it all without first baseman Derrek Lee, sidelined with back spasms.
"We're playing good baseball, but again, we just have to keep going. Can't sit," Piniella said.
DeRosa, who continues to set career highs with each swing, led off the second with a home run, hitting an 0-1 pitch from Jason Bergmann (2-10) to right. He's the first Cub to homer in four straight games since Fred McGriff did so Sept. 20-23, 2001. DeRosa has 18 homers and 77 RBIs; his previous highs were 13 and 74, set in 2006 with Texas.
"I can't explain them, to be honest with you," DeRosa said. "I don't know. I'm getting pitches to drive and I'm not missing them. I have a game plan going into every game, and what I want to do. It worked for the first at-bat, and then all bets are off and I'm terrible for the next two. It's just one of those things -- I'm not missing my pitch."
Jim Edmonds followed DeRosa's homer with a walk, and Soto delivered his blast, which tied the club mark for most home runs by a rookie catcher, set in 1966 by Randy Hundley. It wasn't a day conducive for home runs, as the wind blew in.
"The balls hit today were hit well, and hit on the line and cut through the wind," Piniella said.
There's still time to pad those numbers. Harden has had arm troubles in the past, and a reporter asked Piniella if he considered skipping the pitcher in the rotation after the Cubs clinch.
"Son, we have 32 games to go, and a lot of baseball to be played," Piniella said. "We'll just watch his pitch counts. I think that's ample enough for now."
There's still work to be done.