MILWAUKEE -- Doug Davis is disappointed he didn't adjust his delivery any earlier.
"This game is a game of adjustments," he said. "Wish I could have made the adjustment about 20 starts ago."
Brewers pitching coach Mike Maddux suggested a mechanical change that caused Davis to alter how he rotates his upper body and close off his shoulder.
"I was hitting my spots and had better control," he said after striking out eight in seven innings, allowing four runs, eight hits and three walks.
It also helped that Davis (8-6) was given a seven-run lead. and he improved to 3-0 in his last four starts despite a 6.09 ERA. He got out of trouble in the third when he struck out Phil Nevin and Jacque Jones with the bases loaded.
"It all revolves around your starting pitching," Brewers manager Ned Yost said after his team took two of three from the Cubs.
Francisco Cordero completed the six-hitter, working the ninth for his fifth save in as many chances since Milwaukee acquired him from Texas on July 28.
Chicago pinch-hitter Cesar Izturis walked in the ninth and Aramis Ramirez reached on center fielder Brady Clark's second error of the game. Cordero retired Nevin, then got Jones to hit into a game-ending double play.
"He's got a real mound presence," Yost said. "You could see the warrior come out with runners at first and second."
Mark Prior (1-6) gave up six runs -- five earned -- and four hits in three innings, and all four batters he walked scored.
"From the outset, he didn't have his control. His velocity was pretty good. It's just a matter of control," Cubs manager Dusty Baker said.
Prior is 1-2 with a 6.75 ERA since July 21, when he came off the disabled list after recovering from a strained left oblique muscle. He has walked 28 and hit eight in 43 2/3 innings this season and has not pitched past the sixth.
"It's obviously been a long year," Prior said. "Things haven't been as great as I would have wanted them to be."
Ramirez drove in three runs for the Cubs with a sacrifice fly in the first and his 27th homer -- a two-run drive in the fifth. He has 11 homers in 26 games since the All-Star break.
Chicago had not lost consecutive games since being swept by Washington in a three-game series July 21-23.
Milwaukee loaded the bases in the first on two walks around Jeff Cirillo's bloop single. Prior knocked down Kevin Mench with an inside pitch, and Mench followed with a two-run single off the wall in left.
Rookie Angel Pagan, making his 12th start in left, made a throwing error that allowed the runners to advance, Gabe Gross hit a sacrifice fly, Tony Graffanino was hit by a pitch and David Bell added another sacrifice fly.
Bell and Rivera hit RBI singles in the third following two more walks by Prior, and Graffanino had a two-run single in the fourth off Juan Mateo that made it 8-1. Mateo had been scheduled to start Saturday at Colorado.
"We came back," Baker said. "We just didn't come all the way back."
"Nah, you could see Prior was struggling and we took advantage of it," Yost said.
- Clark's error in the seventh snapped the Brewers' string of 11 consecutive errorless games, which tied the franchise record set in 1979.
- Chicago's Ryan Theriot went 3-for-3. ... Davis is 6-5 in 12 games against the Cubs.