PHOENIX -- Barry Bonds rocked the Chase on Saturday night, even though the Giants did not.

Given a chance to hit with a runner on second and first base open for the only time so far in the series, the left-handed Giants slugger moved ever closer to Hank Aaron's all-time Major League home run record by launching No. 742 into the far reaches of Chase Field.

The two-run shot to deep right-center with two out in the first inning came off Diamondbacks right-hander Edgar Gonzalez. Bonds is now 13 behind Aaron's 755. Aaron has owned the record since 1974, when he passed Babe Ruth to take the lead.

"I don't want to talk about the home runs until we get closer," Bonds said after the Giants dropped a 5-4 decision to the D-Backs, squandering his home run and a 4-0 lead in the process. "We've got to win these games. We can't afford to lose games like this."

It was Bonds' eighth homer of the season, coming in the team's 22nd game. Last year, he didn't hit his seventh until May 28, the day in San Francisco he passed Ruth into second place with 715. Bonds didn't hit his eighth until June 5, the team's 57th game.

Bonds is second in the National League in homers behind Philadelphia's Jimmy Rollins, who has nine.

In two games, Bonds has been on base eight times in nine chances.

That's two hits, five walks (four intentional) and a hit-by-pitch, raising Bonds' on-base percentage to .519 and his slugging percentage to .828, both tops in the National League. Oh, and his batting average is .362.

In the fifth inning, with Omar Vizquel on second, D-backs manager Bob Melvin didn't hesitate to put up those four fingers, not after he was burned in the first.

"That's not my crowning moment right there," Melvin said about his decision to finally pitch to Bonds after walking him three times with a runner on second and first base open Friday. "At some point in time, especially early in the game, you maybe want to try and set a precedent that we're just not going to walk this guy every time. We're not scared to death of him, but the minute the ball leaves the ballpark, you want to crawl into a hole. The base is open every other time I've done it."

It was the third homer of Bonds' career off Gonzalez and 19th here since Chase Field opened in 1998. Bonds also homered off Gonzalez last Saturday in San Francisco, accounting for the only run in a 1-0 Giants victory over Arizona.

Lifetime, he's batting .556 (5-for-9) with five runs batted in against Gonzalez, who lasted five innings and wasn't around when Scott Hairston's three-run, pinch-hit, seventh-inning homer off Vinnie Chulk won the game for Arizona.

Bonds, who is expected to be out of the starting lineup Sunday when the Giants face Randy Johnson, shrugged his shoulders at being on base so often this weekend.

"I'm tired," said Bonds, who has started eight games in a row. "It's wearing me out."