DENVER -- One minor adjustment was all it took Aaron Cook to end a two-game losing streak.

"I threw 75 percent four-seamers today," said Cook, who is primarily a sinkerball pitcher. "I was able to throw it where I wanted to, and that made my sinker look a little bit sharper when I did throw it."

Cook still managed to get 11 groundball outs with his sinker, and his Colorado Rockies beat the San Diego Padres 6-3 Sunday.

"Mainly, I did it to keep the lefties off balance because I had been getting beat a lot down away from lefties," Cook said. "(Teammate) Mike DeJean told me that they had felt too comfortable with me and weren't being stood up at all so I needed to come in hard and in on them."

Cook (9-12) improved to 7-3 lifetime against San Diego. He gave up two runs and five hits in eight innings, striking out five and walking none.

"That was a vintage outing from him," manager Clint Hurdle said. "He went out determined to get things done and got the job done."

Cory Sullivan drove in a career-high three runs with three hits. Matt Holliday hit his 24th homer and drove in two runs for the Rockies.

Adrian Gonzalez and Brian Giles homered for the Padres, in contention for the NL West title and the wild card.

Jake Peavy (7-13) lasted only 4 1/3 innings, allowing six runs and eight hits. He was 3-2 and had given up three or fewer runs in each of his last six starts.

"Jake had good stuff early, but I think he just fatigued there," San Diego manager Bruce Bochy said. "He had a sinus infection for a couple of days and it has taken a lot out of him."

The Rockies got a couple of lucky bounces in taking a 1-0 lead in the second. Holliday singled off Peavy's glove and went to second base when third baseman Russell Branyan's throw got past Gonzalez at first base. Two outs later, Sullivan had an RBI single when his grounder hit the bag at first and caromed into right field.

"I'd love to blame it on that (sinus infection), but I just didn't make a lot of good pitches there in the fifth inning," Peavy said. "I thought they were pretty decent pitches on both of Sullivan's hits that drove in runs."

Colorado loaded the bases with no outs in the fourth on a single by Garrett Atkins and walks to Holliday and Brad Hawpe. Sullivan hit the chalk line in left field for a two-run double to make it 3-0.

Atkins singled and Holliday homered into the left-field seats to start the fifth. Hawpe doubled and Chris Iannetta chased Peavy with an RBI single that made it 6-0.

"Peavy is usually pretty tough on me," Hawpe said. "This time he left a first-pitch fastball up and I got it."

Cook lost his shutout bid in the seventh inning. Mike Piazza singled and Gonzalez followed by hitting a 3-2 pitch over the wall in center field.

Giles hit his 11th homer in the ninth.

"I don't know why I've done so well against San Diego," Cook said. "Maybe they've got a group of guys that have trouble seeing the ball off of me."

Notes

• Padres RHP Chris Young will make his scheduled start on Tuesday. He'd come out of his last start with soreness in his right shoulder.
• Iannetta got his hit and RBI in his major league debut.