De La Rosa (10-8) struck out seven in seven scoreless innings to win his second straight start, retiring the final 11 batters he faced after Bengie Molina's one-out double in the fourth and 17 of his last 19 overall. De La Rosa gave up three hits and pitched perhaps his best outing of the year in his final 2008 start. He also blanked the Giants over seven innings Sept. 1, striking out six and allowing four hits.

"The tempo to everything he does has picked up — his pace, his rhythm," manager Clint Hurdle said. "He's just got so much more confidence. He might have just saved his best for last. From where he came from to where he's finished, he's made a lot of positive strides for us."

Barry Zito (10-17) struck out six and walked four over eight innings in the $126 million Giants left-hander's last start of the season. After beginning the year 0-8, Zito bounced back for a respectable finish and won four of his final six decisions.

"I think I pretty much got to rock bottom this year," Zito said. "I know what that's like and don't need to worry about it anymore."

After Zito retired Barmes on a flyout on the first pitch of the game, Troy Tulowitzki hit a popup that both shortstop Ivan Ochoa and second baseman Eugenio Velez went for on Velez's side. They miscommunicated, Velez pulled off the play at the last second and the ball glanced off Ochoa's glove for a two-base error.

Barmes, who had four hits, scored four runs and drove in four in a 15-6 win a night earlier, flied out in his first three at-bats before hitting a leadoff homer in the seventh. It was Barmes' career-best 11th of the season.

De La Rosa, who became Colorado's third pitcher with 10 or more wins, had some control problems in the second. Molina led off with a single, moved to second on a passed ball and reached third on a wild pitch that glanced off catcher Chris Iannetta's glove and popped straight up before he caught it. Molina then tried to score on another errant pitch but was thrown out at the plate.

De La Rosa joked about the series of plays, saying, "That was the plan."

"We can't figure him out," Giants manager Bruce Bochy said of De La Rosa. "We're having a tough time with him. He does have good stuff and kept us off balance. I don't think we hit a ball hard off him except for Bengie all night."

After Manuel Corpas allowed pinch-hitter John Bowker's RBI single in the eighth, Brian Fuentes finished for his 30th save in 34 opportunities. Fuentes had the tying run aboard with one out in the ninth after allowing a walk and a single, but struck out Aaron Rowand and got pinch-hitter Pablo Sandoval to line out to first.

The NL West already had been decided earlier in the day when the Arizona Diamondbacks lost at St. Louis to give the division title to the Los Angeles Dodgers. Colorado finishes the year at Arizona this weekend, while the Giants host the rival Dodgers.

"It's probably going to take away a little bit of the luster," Bochy said. "I'm not going to do anything different."

Same goes for Hurdle, who said he might give a start in the outfield to Double-A callup and Olympic bronze medalist Dexter Fowler that Fowler might not have had otherwise.

"My guys want to play for all the right reasons," Hurdle said. "It's going to be business and baseball as usual for us. I'm not going to pull the plug on anything."

The Giants discussed shutting down starter and Cy Young Award candidate Tim Lincecum, but the hard-throwing right-hander didn't want to end his spectacular season on a frustrating loss at the hands of the Rockies on Tuesday night.

Notes: Fuentes reached 30 saves for the third time in his career. ... Outgoing Giants owner Peter Magowan was recognized near home plate before the game. He is retiring as managing partner next week after 16 years. ... Giants LF Fred Lewis, recovering from surgery to remove a bunion from his right foot, had about eight stitches removed one day shy of two weeks after the operation. "Every step is a good step," he said. ... New Golden State Warriors forward Ronny Turiaf attended the game. ... San Francisco LHP Noah Lowry, who has missed the entire season following surgery for a nerve irritation in his forearm, was examined by Dr. Lewis Yocum for his current elbow problem and surgery is being discussed. ... The Giants renewed their contract with Double-A Connecticut through 2010. ... Friday night's game against the Dodgers was changed from a 7:15 p.m. start to 7:35 p.m.