"You never know when you're going to get on one of those streaks," Tulowitzki said. "I've definitely put in the work in the batting cages. To have success on a day we win is rewarding."
Tulowitzki is batting .353 (12 for 34) in his last nine games, although he's still looking for his first home run in over two weeks. He had a double in each of his previous three games.
"This is what he has coming to him," Rockies manager Jim Tracy said. "Several of the balls he's hit have been vicious line drives that end up in a fielder's glove. Sooner or later those things are going to turn."
Tulowitzki was also involved in the key defensive play of the game. After Andres Torres doubled with one out in the fifth, Chacin and Tulowitzki hooked up on a pickoff play.
"That's a daylight play I run with the pitchers," Tulowitzki said. "It's pretty successful when it's run right. It was a big play."
Chacin (6-4) allowed one run and four hits to end a personal two-game losing streak and help the Rockies win in San Francisco for the first time in five games.
"He gave me the inside move," Chacin said of the pickoff. "When I looked back at second I saw Torres really off the base. I just tried to throw the ball accurately."
Giants manager Bruce Bochy said Torres wasn't thinking about stealing third.
"Andres just got picked off," he said. "He wasn't going anywhere. He just kind of got in no man's land there, and we're getting to the heart of our order and his pitch count was getting up there. That was not a good play for us."
"He struggled with his command a little bit but when he needed to make pitches, he made pitches," Ross said of Chacin. "He kept us off balance throwing breaking balls and changeups in hitter's counts and getting us out front."
Chacin said his fastball command was not there in the early innings, but his other pitches were effective.
"The change was good today," Chacin said. "It helped me set up other pitches until I could start to throw the fastball for strikes. I was just trying to find a way to get outs and get out of innings."
Tulowitzki singled and scored on a throwing error by shortstop Brandon Crawford in the fifth, then added an RBI single in the sixth that gave the Rockies a 2-0 lead. The star shortstop is a career .298 hitter in San Francisco.
Ross hit his fifth homer with two out in the bottom half of the sixth.
The Rockies found a way to win despite their continued lack of production. They have scored three runs or fewer in 12 of their last 14 games and are 4-10 over that span.
Bumgarner faced the minimum through four innings. He struck out six and walked one, but is 0-3 with a 4.39 ERA in five home starts this season.
The Giants have lost three straight one-run games at home after winning their first 11 such contests at their cozy waterfront ballpark.
Giants C Chris Stewart made his 15th career start. ... The Rockies placed RHP Matt Daley on the disabled list and recalled LHP Rex Brothers. ... Tulowitzki is hitting .421 (8 for 19) on Colorado's road trip. ... The start of the game was delayed 20 minutes by rain. ... A fan was struck in the face by a foul ball and had to be led off by medics. ... An MRI revealed a hairline fracture in Giants 1B Brandon Belt's left hand. He's expected to go on the disabled list Sunday and will be replaced by Conor Gillaspie, who appeared in eight games with the Giants in 2008.