Colorado (11-11) at San Francisco (12-9)

Having put together the best April of his career, San Francisco Giants left-hander Barry Zito(notes) is finally living up to his contract.

Zito looks to continue his outstanding start and turn in another dominant performance against the Colorado Rockies on Friday night at AT&T Park.

Zito (3-0, 1.32 ERA) is finally pitching to his Cy Young Award-winning form, which led the Giants to ink him to a $126 million deal after the 2006 season. He came into this year with a 4.82 ERA prior to May 1, but has turned in the best first month of his career through four outings.

Zito, who went 31-43 with a 4.30 ERA in his first 98 starts with the Giants (12-9), had his best performance yet his last time out. He held St. Louis to three singles over eight innings while striking out 10 - tying his high with San Francisco - in a 2-0 victory Saturday.

“I’m just trying to have fun playing baseball and pitch,” Zito said. “Not make it more complicated than it is.”

He is certainly making it difficult on opposing hitters, holding opponents to a .161 average - lowest in the NL.

“Really, every start, he has been that good,” manager Bruce Bochy told the Giants’ official website. “He’s in a nice zone right now. It’s something we need, too.”

There’s plenty of reason to believe Zito can continue his roll in a matchup with Colorado (11-11). He’s 4-2 against the Rockies in 11 career starts with a 1.98 ERA - easily his best against any opponent - and went 2-0 with a 0.95 ERA in the last four matchups, winning the last two.

Colorado scored 23 runs in the past two games, but after a 12-1 victory over Arizona on Tuesday, it couldn’t close the series with a win. The Rockies rallied from a 6-0 deficit in the first inning to take an 11-6 lead, but lost 12-11 in 10 innings.

“These are the toughest ones to lose,” shortstop Troy Tulowitzki(notes) said. “We battled back, got ahead and let them go ahead. We could have given in when it was 6-0. We didn’t. At the same time, it was a game we should have won and didn’t.”

Tulowitzki, hitting .400 over his last 10 games, is 5 for 29 (.172) with eight strikeouts against Zito.

San Francisco will also be trying to forget about an extra-inning loss. Tim Lincecum(notes) handed the bullpen a 4-1 ninth-inning lead against Philadelphia on Wednesday, but the Phillies rallied to win 7-6 in 11 innings.

Closer Brian Wilson(notes) hadn’t allowed a run before being charged with two Wednesday.

Colorado’s Aaron Cook(notes) (1-2, 5.01) should bring plenty of confidence to the mound after his latest start. Cook went the distance against Florida on Saturday, yielding five singles and striking out four in an 8-1 win.

“I went out there and just tried to repeat the same delivery, time and time again, without putting any more or any less effort into any pitch, and the ball just came out of my hand good,” Cook said.

Cook went 1-1 with a 5.40 ERA in two starts against the Giants last season.

Colorado has lost seven of nine in San Francisco.