DENVER -- Jeff Francis has emerged as the Colorado Rockies' staff ace, but his biggest contribution Monday came with his bat.
Francis' one-out double started a seven-run third inning, and Chris Iannetta's two-run triple highlighted the rally as the Rockies opened a crucial six-game homestand with a 7-4 win over the San Francisco Giants.
The Rockies, who started the day five games back in both the National League West and the NL wild-card race, improved to 71-66. They are five games above .500 for the first time since Aug. 15.
A year ago, the Rockies were 10 games under .500 and out of the postseason hunt.
"It's a lot more fun," Francis said. "Guys out here are playing for the team, playing for the guy next to you. This time last year guys were going out and maybe playing a little bit for themselves. Now they have no choice but to do otherwise."
Francis (15-6) went 5 2/3 innings, giving up three runs and nine hits. His 15 wins are the most by a Colorado left-hander since Shawn Estes had 15 in 2004.
"Those are bonuses," Francis said. "Right now, we're trying to win games."
Manny Corpas got three outs for his 13th save in 15 chances, and his 13th straight since replacing Brian Fuentes as closer.
Colorado's big third inning came mostly at the expense of Giants starter Matt Cain. The Rockies roughed up Cain (7-14) for six runs and five hits in the inning before he was lifted in favor of reliever Pat Misch.
Francis battled Cain, fouling off four pitches before doubling to center.
"I hit it obviously in the right spot," Francis said.
Francis scored on a single by Kaz Matsui, and Matt Holliday's sacrifice fly scored Willy Taveras. After consecutive walks to Todd Helton and Garrett Atkins loaded the bases, Brad Hawpe lined a two-run single to right field.
Misch came on and gave up an RBI single to Troy Tulowitzki and a triple to right to Iannetta.
Taveras had three hits and Helton and Iannetta had two hits each.
"Very rarely do you win when you score in one inning here and you don't add on," Rockies manager Clint Hurdle said. "It was a big inning. It was a good inning. It was enough for us to win a game."
Cain, who went 2 2/3 innings, had the shortest start of his career in a ballpark where previously he was dominant in 2007. In his two prior starts at Coors Field this season, Cain was 1-0 with a 0.69 ERA in 13 innings. He started strong Monday, striking out five of the first eight batters he faced before Francis' double.
"Francis, that's a huge at-bat there, then he just couldn't get out of it," Giants manager Bruce Bochy said of Cain. "It's a game we let get away from us, because Matty had good stuff. It's a shame we couldn't get out of that inning."
The Giants got two back in the sixth on a pair of RBI singles from Pedro Feliz and Kevin Frandsen, chasing Francis. Reliever Jeremy Affeldt ended the threat by getting Ray Durham to fly out to center.
Randy Winn's ninth homer of the season cut the lead to 7-4 in the seventh.
Bengie Molina led off the second inning with his 15th homer to give San Francisco a 1-0 lead.
The Rockies have won four of their last five games and seven of their last 10.
Francis is two shy of the franchise record for wins, set by Kevin Ritz in 1996 and matched by Pedro Astacio in 1999. ... Francis' double in the third inning was his third of the season and fifth in his career. ... Cain's shortest start before Monday was May 3 against Philadelphia when he went three innings and gave up seven earned runs.