But Brad Hawpe, who had been struggling, homered with one out in the ninth for the Rox's only run off Zito, who struck out seven in 8 1/3 innings. After Ian Stewart and Yorvit Torrealba singled off Sergio Romo, super-sub Seth Smith singled for two runs off Jeremy Affeldt and Todd Helton singled against closer Brian Wilson (32 saves), the Rockies brought Clint Barmes to the plate as the potential go-ahead run.
Alas, Barmes, after taking two pitches he thought were balls, flied to center field. There was no miracle swing, like Ryan Spilborghs' 14th-inning grand slam to beat the Giants on Monday night.
The Giants have a momentum feast. But a three-run ninth represents at least a little snack, even though the four-game losing streak matches the longest since Jim Tracy took over for Clint Hurdle as manager on May 29 and lost his first four games.
Maybe the momentum the Rockies carry into Sunday's game against the Giants and formidable pitcher Matt Cain amounts to the fumbled kernels of popcorn and garlic fries that the seagulls call a meal. But still.
"To be swinging the bats the way we were for eight innings, and to have the winning run standing at home plate, I think that's extremely encouraging," Tracy said. "If we had gone very, very quietly in the ninth inning, there would have been an awful lot to think about."
Rockies right-hander Jason Marquis (14-9) had little chance to win and match his career high for wins in a season. Pablo Sandoval homered for the second straight night, a leadoff shot into McCovey Cove in the second inning for his 21st homer of the year.
The big inning was the sixth, when the Giants scored three runs, one on Juan Uribe's double down the third-base line, one on a Nate Schierholtz sacrifice fly and the other on Eli Whiteside's line triple past diving center fielder Eric Young Jr.
Marquis said he would take back only the pitch to Whiteside. But with the Rockies doing nothing offensively, it was only a matter of time before the Giants would feed off the momentum of their pitcher.
"Every little thing that can change the momentum, the good teams are going to pick up on it," Marquis said.
The Rockies' biggest chance against Zito came with the bases loaded in the seventh, but Hawpe flied to left on a Zito fastball.
But the All-Star Hawpe, whose homer to left was his 19th but just his fourth since the All-Star break, started what the Rockies hope is some good offensive feeling that can carry into Sunday.
"We're not going to give up -- that's pretty known," said Barmes, who slammed his bat in frustration after the out, mainly because he felt the borderline pitches early in the count should have gone his way. "It would have been nice to get on base and keep it going, but it didn't work out."
Sunday will be the seventh meeting between the Rockies and Giants in each team's last 10 games. Sunday is the tiebreaker of this mini-series. The Rockies will come back Sept. 14-16.
"We still have a month left, but these games are big for us and we have to take advantage of them, especially at home," said Schierholtz, who plays for a Giants club that has the NL's highest home winning percentage (43-21, .672).
The first six games have given each team's fans to break into heartfelt, and beautifully unoriginal, chants.
After Spilborghs' slam Monday, with the Dodgers heading to town and the fans having prematurely forgotten about the Giants, Rockies faithful nearly drowned out the postgame TV show by yelling "beat L.A." After Zito departed Saturday night, a "Bar-ry" chant started. A certain home run-hitting guy used to attract that at AT&T Park.
"The enthusiasm we're playing with and the fans are playing with, both here and in Colorado, is just awesome this time of year," Hawpe said. "But regardless of the outcome, we've got to realize we've got 30-plus games left."