SAN FRANCISCO -- Third baseman Nolan Arenado didn't understand all the commotion around his locker Friday night. All he'd done was account for two of the Colorado Rockies' 17 hits.

Such is the way it is sometimes with the high-scoring Rockies. You can be just another contributor even you've just hit two home runs.

Right fielder Carlos Gonzalez returned to the starting lineup with five hits, including a tie-breaking double in a three-run seventh inning, and Arenado added his second two-homer game in four days, propelling the Rockies to an 8-6 victory over the San Francisco Giants in the opener of a three-game series Friday night.

The last-place Rockies, who swept a three-game series at AT&T Park in April, made it seven wins in 10 games against the defending World Series champs this season.

"We've got a great ballclub," winning pitcher Chad Bettis said of the 33-40 Rockies. "The pitching staff, we just need to keep ourselves in the ballgame. We have a lot of nights like this. We have the power."

Gonzalez, who hadn't started since spraining his left hand during an at-bat last Sunday, contributed a triple, double and three singles to a 17-hit attack that helped the Rockies begin a 10-game trip on a positive note.

In all, six Rockies contributed two or more hits to the club's fifth win in its last six games.

"We're having great at-bats as a team," Arenado observed. "We're getting production when we need it. You can go right down the line."

After San Francisco had rallied into a 3-3 tie with a two-run sixth, Rockies center fielder Charlie Blackmon singled with one out in the seventh against Giants starter Tim Hudson.

A two-out walk to shortstop Troy Tulowitzki set the stage for Gonzalez, who greeted left-handed reliever Javier Lopez with a liner down the right-field line that plated Blackmon with the go-ahead run.

The Giants then elected to intentionally walk Arenado, who had belted a three-run homer in the previous inning. But the strategy failed when first baseman Ben Paulsen, like Gonzalez a left-handed hitter, grounded a two-run single to increase the Colorado lead to 6-3.

"It's almost do-or-die for us," Arenado said in stressing the importance of the win and of the road trip in general. "It would be nice going into the All-Star break playing well. That would give us a chance."

Gonzalez's triple came with two outs in the ninth, after which he scored on a passed ball on Giants catcher Andrew Susac for a 7-3 lead.

Arenado followed with his second homer, a solo shot, to complete the Rockies' scoring. The pair of home runs gave him 22 on the season and helped extend his hitting streak to 13 games.

"I'm just trying to hit the ball hard," said Arenado, whose multi-homer game was his fourth of his career. He also hit a pair Tuesday against Arizona.

"They've been going out," he continued. "I don't have an answer for that."

Gonzalez matched a career-best with five hits. He had accomplished the feat three times previously. He also scored three runs.

The Rockies took a five-run lead to the bottom of the ninth before things got interesting. Thanks to wildness by Colorado's fifth pitcher, right-hander Tommy Kahnle, San Francisco scored three times to get within 8-6.

But after walking three batters, throwing a wild pitch and allowing run-scoring hits to center fielder Gregor Blanco and second baseman Joe Panik, Kahnle struck out third baseman Matt Duffy and first baseman Buster Posey with the potential tying runs on base.

"It's never easy," Rockies manager Walt Weiss assured. "I would have liked to coast to the finish line. But we knew better."

Bettis (4-2), who allowed the two-run sixth that got the Giants even, got the win. He allowed three runs on six hits in six innings. He walked two and struck out three.

Paulsen finished with three hits, and Tulowitzki, catcher Nick Hundley and left fielder Brandon Barnes added a pair apiece for the Rockies.

Hudson (5-7), who reportedly will go on the disabled list next week when right-hander Matt Cain returns from the DL, took the loss. He was roughed up for 10 hits and five runs in 6 2/3 innings. He walked one and struck out six.

"We'll talk," Giants manager Bruce Bochy said of Hudson's future without disclosing any details.

Susac smacked a home run, his second, and Panik had a double and two singles for the Giants, highlighting a nine-hit attack.

"They were fighting," Bochy assured. "It's all you can ask. It didn't pan out tonight."

The Giants' loss snapped a two-game winning streak. They haven't won three in a row since May 19-21.

NOTES: Rockies 3B Nolan Arenado's four RBIs gave him 64 for the season, allowing him to surpass last year's total of 61. ... Giants CF Angel Pagan (bruised left knee) is likely to miss the whole series -- and possibly more -- because of swelling in his knee that resulted from running into the center-field wall during Thursday's win. X-rays were negative and an MRI revealed no structural damage. ... Giants RHP Matt Cain (strained flexor muscle in right arm) came through his final injury-rehab start for Triple-A Sacramento healthy and is expected to be activated off the disabled list next week. ... The Giants began the day by placing LHP Jeremy Affeldt (stiffness in his left shoulder) on the DL, replacing him on the active roster with RHP Mike Broadway, who was recalled from Sacramento. ... Before the game, the Rockies activated RHP Rafael Betancourt (sinus infection and vertigo) from the DL and sent RHP Justin Miller to Triple-A Albuquerque. Miller had been the winning pitcher in the Rockies' 6-4 win over the Arizona Diamondbacks on Thursday. ... The Rockies also announced before the game that LHP Jorge De La Rosa, who had be pulled from Thursday's game in the sixth inning after reopening a cut on his left middle finger, has been bandaged up and is not expected to miss his next scheduled start.