Alex White tossed four effective innings on the mound and blasted his first career home run as the Colorado Rockies knocked off the San Francisco Giants, 6-5, in the opener of a three-game series at Coors Field.

White gave up just one run on six hits with a pair of strikeouts and Guillermo Moscoso (2-1) claimed the win with two innings of relief work. Rafael Betancourt tossed a perfect ninth to secure his 28th save of the season.

Chris Nelson clubbed an RBI triple and Josh Rutledge added an RBI double for the Rockies, who were swept in a three-game set over the weekend by the Philadelphia Phillies. Jordan Pacheco contributed an RBI in the victory.

Buster Posey belted a two-run homer and Hunter Pence blasted a solo shot for the Giants, who took two of three from the Los Angeles Dodgers over the weekend.

Ryan Vogelsong (12-8) absorbed the loss after yielding four runs on six hits over five innings.

"He's one of our guys, he's going to be out there," Giants manager Bruce Bochy said. "We have all the confidence in the world in him."

The Rockies struck first with a pair of runs in their first at-bat. Tyler Colvin started the inning with a rocket double to deep center field and scored on a double by Rutledge. Rutledge then moved to third on a groundout by Carlos Gonzalez and crossed the plate via a single by Pacheco.

Pence pulled the Giants within one in the second after he led off the frame with a towering shot over the wall in left.

White got a hold of a fastball from Vogelsong in the home second and blasted it over the wall, extending the Rockies lead to 3-1.

Ramon Hernandez began the Colorado fourth with a ground-rule double. Pinch- runner Wilin Rosario moved to third when Nelson reached on an error by Brandon Belt, and scored on a double-play groundout by Charlie Blackmon.

An RBI groundout by Belt in the sixth pulled San Francisco to within 4-2, but the Rockies added two more runs in the home half of the inning.

With two down in the frame, Rosario reached first on an error by Pablo Sandoval and scored when Nelson belted a triple into the left-center field gap. Blackmon then singled home Nelson to make it 6-2.

"We took advantage of an error, like we did a few days back," Rockies manager Jim Tracy said. "We took advantage of an error by Sandoval and put together three straight two-out hits and put some runs on the board."

Posey rocketed a high fastball from Rex Brothers over the wall in right-center for a two-run shot to make it 6-4 in the seventh, and Pagan doubled home Crawford in the eighth, trimming the deficit to one.

Betancourt went through the heart of the Giants order -- Posey, Pence and Belt -- with ease in the ninth to wrap up the win.

Game Notes

The Giants fell to 19-7 on the road since the All-Star break ... Vogelsong lost for the first time in his career against the Rockies, he had been 5-0 entering play on Monday ... San Francisco leads the season series between the teams, 8-4 ... Colorado improved to 20-27 against intra-division competition this season.