SAN FRANCISCO — For most of his outing, Barry Zito had a large lead that would make most pitchers plenty comfortable.

Zito never allows himself to think that way. Not with all the ups and downs of his Giants tenure.

"I think the mindset that it's easier because you have a lead will tie the game up quickly," he said.

Buster Posey drove in three runs, Zito pitched another gem and contributed with his bat, and the San Francisco Giants beat the Colorado Rockies 10-0 on Wednesday to complete a three-game sweep.

Staked to a quick lead, Zito (2-0) won his 11th straight decision, including last year's postseason. San Francisco earned its 16th consecutive victory in games he has started.

"It's hard to speak about a stretch or a run or the past, really," Zito said. "Today the boys came out swinging. They were starting to click on all cylinders offensively, which was great because a lot of people underestimate our offense. And days like today really show what we can offer."

Zito has thrown 14 scoreless innings so far<NO1>, the deepest the lefty has gone without giving up a run to start a season in his 14-year career.

Posey hit an RBI triple in the first, a run-scoring double in the second and an RBI single in the fifth. He scored twice.

The Giants won their ninth in a row overall against Colorado.<NO1> They also have beaten the Rockies nine straight times at AT&T Park.

Andres Torres hit a two-run single, Joaquin Arias singled home a run in a rare start and Marco Scutaro hit a sacrifice fly as the Giants went ahead 7-0. They chased Jeff Francis (1-1) in the second inning for the shortest start of his career.

"I'd miss a pitch and they'd whack it. I'd make a pitch and they'd whack it," Francis said.

The Giants had a season-high 16 hits a day after getting 14.

Zito had an RBI single in the fifth. He singled the next inning for his first career multihit game<NO1>, prompting a standing ovation from the sellout crowd of 41,606 and chants of "Barry! Barry!" He has a four-start hitting streak dating to the 2012 postseason<WC> — five hits in his last eight at-bats, with eight sacrifice bunts.

"He's going to have a shift soon, probably," Posey cracked.

Zito allowed seven hits in seven innings, struck out four and walked one. Javier Lopez and Chad Gaudin completed the seven-hitter.

Zito was part of his second shutout already this season, and he hasn't lost since Aug. 2 against the Mets.

"You can't have more confidence out there than what Barry has right now," Giants manager Bruce Bochy said. "It's fun to watch when a pitcher's on and hitting his spots. It's a thing of beauty. He's as tough a competitor as I've ever been around."

The Rockies arrived in San Francisco riding a five-game winning streak and left with a three-game skid. <NO1>Colorado had homered in each of its first eight games before being shut out for the first time in 2013.

"I was expecting to come in here and win a series," rookie manager Walt Weiss said. "The Giants played well. This one today got away from us early. We look at it as three games of 162."

Giants slugger Pablo Sandoval had the day off to give his body a break. Sandoval missed 13 games late in spring training with an inflamed nerve in his right elbow. "We're being cautious with him," Bochy said.

Hunter Pence had his seven-game hitting streak snapped for the Giants.