SAN FRANCISCO -- The Giants' offense finally started to come alive this week behind the bat of Barry Bonds, but it's taken a nosedive the past two days, most recently in a 5-0 loss to the Pirates on Sunday.

The Giants' inability to generate timely hits cost them with a three-game series sweep courtesy of the Pirates, the worst team in the National League. Bonds has held up his end of the bargain since hitting No. 756.

In a Tuesday postgame news conference, Bonds told reporters he would start hitting more consistently from here on out, and he has. Bonds is 6-for-10 with four walks since the record breaker. He broke the record two more times this week and has hit safely in four of his last five games.

For a while, the rest of the lineup was behind him. The Giants generated 19 runs in four games, beginning with Bonds' record-breaking night, but their offense diminished on Saturday and disappeared completely on Sunday.

When you look at starting pitcher Barry Zito's numbers, three runs in six innings is not bad, but the Giants gave him no run support. They put runners in scoring position in the first three innings without bringing one home. The Giants collected only one more hit after the third inning and their last 17 hitters were retired by Tom Gorzelanny, who threw his first career shutout and complete game.

It took Zito two innings to warm up, and was lucky that it took the Pirates just as long. Zito skated when he walked the first three batters to load the bases and escaped with zero runs in a 32-pitch first inning.

With a doubleheader on tap the Giants needed length out of Zito, so when manager Bruce Bochy saw him struggling he took a trip out to the mound.

"We needed him to get us somewhat deep in the game," Bochy said. "I told him that when I went out there, 'You're going to have to figure this out. I'm not going to get somebody up,' so that was really critical of him to give us some innings."

Zito did figure it out and pitched a perfect third, fourth and fifth innings before giving up a two-run home run to Josh Phelps in the sixth. It was one mistake in an otherwise good outing.

"Obviously, I don't want to give up that homer in the sixth. That kind of puts the game more out of reach," Zito said.

Zito walked slowly off the field to a few boos. He hasn't pitched as well as expected this year, but the Giants' losing season shouldn't rest squarely on his shoulders. Despite Zito's losses, his curveball is still awe inspiring and there is something impressive in the way he keeps plugging away through the first losing season of his seven-year career.

"I wish I could snap my fingers and have it all back, but you just got to build off the little things," Zito said.

The Pirates added two more runs in the seventh inning off reliever Vinnie Chulk. Chulk remained in for two innings to save the bullpen for Monday's doubleheader. He pitched a perfect eighth, and Jack Taschner added a perfect ninth.

After the game the Giants quietly packed up for Pittsburgh, where they will make up two April rainouts. They have 19 more games without a day off. If they lose both games Monday they will take over last place in the National League.

"With no days off coming up in the next couple of weeks it's going to be tough for us," Zito said. "But we've just got to battle through it, and if they need me I'll go back out there in the bullpen."