Tyler Chatwood pitched into the seventh inning and Wilin Rosario stroked a two-run double to send Colorado over the Padres, 4-2, in San Diego's 10th consecutive defeat.
Chatwood (5-2) allowed five hits and a pair of runs over 6 2/3 innings. Rafael Betancourt notched his 12th save of the year and first since May 28.
Everth Cabrera and Kyle Blanks drove in a run for the Padres, whose current skid is their longest since a 10-game slide Aug. 26 - Sept. 5, 2010. The club record losing streak is 13, May 8-21, 1994.
Edinson Volquez (6-7) was charged with eight hits, four walks and four runs over 5 1/3 innings in the opener of this three-game series.
"He was a little erratic at times. He tried to reel it back in," Padres manager Bud Black said. "Overall his stuff was good. He was a little erratic with the heater from the get-go and they capitalized on a couple of breaks."
Corey Dickerson walked on four pitches to start the game. After Michael Cuddyer legged out an infield hit with one out, Rosario doubled to the gap in left-center.
The Rockies padded their lead to 4-0 in the sixth. Todd Helton walked and Tyler Colvin hit a one-out single to put runners at the corners. Jonathan Herrera put down a perfect squeeze bunt to plate Nolan Arenado. After Chatwood walked to fill the bases, Brad Brach, who recalled from Triple-A Tucson Monday, gave up a sacrifice fly to Dickerson in the left field corner.
Chatwood got a scare in the sixth when he took a comebacker off his right ankle. He received medical attention and made some warm-up pitches, but remained in the game.
"He bounced back even after taking the ball off the leg," Rockies manager Walt Weiss said. "He toughed it out and did exactly what we needed,"
San Diego loaded the bases against Chatwood in the seventh and Cabrera walked on an inside pitch to force in a run. Rex Brothers then took over on the mound, but Blanks, in a pinch-hit role, sent a grounder to Arenado, who was late getting the ball out of his glove. Blanks beat the throw at first, but Chase Headley popped out to second to end the inning.
Betancourt, who was on the disabled list nearly a month due to a right groin strain before returning to the mound June 29, put two men on base in the ninth, but pinch-hitter Mark Kotsay flied out to left to end the game.
Colorado leads the season series, 9-2, including winning all four meetings at Petco Park ... Volquez fell to 3-6 lifetime against the Rockies ... The Padres opened a spot for Brach by sending pitcher Robbie Erlin to Tucson ... The Rockies placed pitcher Roy Oswalt on the 15-day disabled list with a left hamstring strain, and recalled outfielder Charlie Blackmon from Triple-A Colorado Springs.