SAN FRANCISCO -- Striding across the clubhouse after a half-hour soaking in the hot tub late Wednesday night, Barry Bonds said it was too soon to get serious about his pursuit of Hank Aaron at the top of Major League Baseball's all-time home run list even though the first of 2007 is out of the way.

"It's not a countdown yet," the Giants slugger said after homering off Padres starter Chris Young in his fifth plate appearance of the season, giving his club a short-lived 1-0 lead in what turned out to be a 5-3 loss. "I'm not close enough yet. Not at all."

Asked when the countdown would begin in his mind, Bonds added: "When it's about 750. At 750 you can count down, not any time soon. But you better hope it's not at the end of September. Y'all can leave and come back then."

For those not counting down, Bonds smacked his 735th home run with two out and no one on in the first inning at AT&T Park. He now trails Aaron by 20 homers. The Hammer hit 755 in his 23-year career that ended in 1976.

Bonds, beginning his 22nd season -- the last 15 with the Giants -- hit his first homer in the team's second game. Last year, one in which he returned from a trifecta of 2005 surgeries on his right knee, Bonds didn't hit his initial homer until April 22 at Colorado. It was the club's 17th game.

It also took him until May 28 to hit seven, giving him 715 to pass Babe Ruth into second.

But Bonds is already proving that 2006 is no reflection on 2007. Already, he has stolen a base and then was thrown out at the plate on a chancy baserunning gamble. Playing left field Wednesday night, he scampered toward the line, making a basket-type catch on a Brian Giles drive to end the top of the third.

Bonds' momentum propelled him toward his club's third-base-side dugout where he went into a squat position. Had he hurt his knee? Tweaked a hamstring? Needed to catch his breath? What was bothering him?

"My age was bothering me," said Bonds, who will turn 43 on July 24, but so far is playing like he's 33. "It was a long run for somebody my age. Just long. It was cold out there. I got a little tight, but that was it."

Bonds homered to left-center on a 2-and-2 pitch off Young in relatively the same spot near the front of the bleachers that he smacked his 700th against Padres ace Jake Peavy on Sept. 17, 2004.

It was his 86th homer against the Padres, far and away his most against any team, and 145th in the park that opened on McCovey Cove in time for the 2000 season. The latter figure is also the most he's hit in any yard.

The homer was his first against Young, making the right-hander the 435th pitcher to allow a homer in Bonds' career.

Bruce Bochy, who took over the Giants this season, was the Padres' manager when Bonds hit many of those homers against his former team, so he said it was nice to be on the other side for a change. Of course, for 12 years Bochy was able to run out Trevor Hoffman to close tight ballgames and he had to watch from the other dugout in the ninth inning as the right-hander retired the side in order to record career save No. 483 to extend his Major League record.

"That's all behind me now," Bochy said.

Bonds was in the on-deck circle when Omar Vizquel lined out to short, ending the game.

"He made a great effort catching that ball and put us in the lead," Bochy said about Bonds. "That's what you're hoping for. We couldn't hold on there, but he had a nice game."

The run scored on the homer was Bonds' 1,481st as a Giant, giving him the all-time club lead in that category since the Giants moved from New York to San Francisco in time for the 1958 season. Willie Mays, Bonds' godfather, had 1,480.

Continuing the countdown, the hit pulled Bonds within 157 of 3,000 and his first RBI of the season puts him 69 away from 2,000.

But Bonds wasn't having any of it.

"I don't want to talk about myself," Bonds said. "We're just trying to get ourselves going right now."