Updated

Barry Zito tries to follow up a brilliant season debut on Wednesday when the San Francisco Giants go after a three-game sweep of the Colorado Rockies at AT&T Park.

Zito was terrific against the St. Louis Cardinals, as he limited them to just three hits over seven scoreless innings and retired 15 of 17 batters beginning with the first inning's final out. He also struck out four and walked three batters.

"When he's really locked in, he's able to start locating inside, not only with the fastball, but throwing the cutter in on the hands, regardless of velocity," Giants reliever Javier Lopez said. "That's what you tend to appreciate because there's never a predictable sequence for him and that's the best part about his game."

Including the postseason, San Francisco has won the last 15 times that Zito has started, a stretch that dates all the way back to Aug. 7, 2012. That streak could be extended on Wednesday, as Zito hasn't lost in 11 starts against the Rockies and owns a 7-2 lifetime mark against them with a 2.61 ERA in 20 games (18 starts).

Colorado will pin its hopes on a veteran lefty of its own in Jeff Francis, who was almost as good as Zito in his debut. Francis beat the San Diego Padres, holding them to a run and five hits in six innings.

"From the first inning, I was hitting the glove," Francis said. "I gave up a run in the first, but it was an infield single and a broken-bat hit. I knew that I was throwing the ball the way that I was expecting to, and it was probably only a matter of time before our guys started scoring runs."

Francis is just 7-9 in 19 starts against the Giants with a 5.38 ERA.

Colorado lost its eighth straight game in San Francisco on Tuesday, as Angel Pagan drove in the winning run in the eighth inning to lift the Giants to a 9-6 win. Brandon Crawford hit a three-run home run and scored twice while Hunter Pence drove in a pair of runs for San Francisco, which has won five of eight to start the season.

Tim Lincecum was tagged for six runs on four hits with four walks and seven strikeouts over six innings of work. Santiago Casilla (1-0) pitched a perfect eighth for the win.

"You got to feel good after the team wins," said Lincecum. "Especially coming back from the hole I put them in there in that second inning."

Dexter Fowler and Josh Rutledge each drove in a pair of runs while Troy Tulowitzki hit a solo homer for the Rockies, who had won five straight coming into the series.

"They won a championship playing like that," said Colorado manager Walt Weiss. "They string together a lot of good at-bats."

Juan Nicasio pitched five-plus innings and was charged with four runs on five hits along with five walks and two strikeouts. Matt Belisle (0-1) gave up two runs on three hits over 1 2/3 innings to take the loss.

The Giants won 14 of 18 meetings against Colorado last season, marking their highest-ever win total against the Rockies in a single season.