MILWAUKEE -- Yovani Gallardo only heard his teammates say "good job" as he left the mound in the seventh to end his major league debut.

But as Gallardo walked back to the dugout to a standing ovation, there stood the highly touted young infield of Prince Fielder, J.J. Hardy, Rickie Weeks and Ryan Braun soaking in the moment.

"We were all standing on the mound after he left and I was looking at those kids and Prince goes, 'Man, he's cool. He's just nice and calm and cool,'" said Brewers manager Ned Yost. "I said, 'Yeah, he's just like you guys. He's a stud.'"

Fielder hit his NL-leading 26th home run, Gallardo dazzled through 6 1/3 innings and the Milwaukee Brewers held off the struggling San Francisco Giants 5-4 on Monday night.

Barry Bonds, with 748 career home runs, went 1-for-2 with a double in the sixth and two walks as San Francisco dropped its fifth game in a row. The Giants have lost 17 of 23 overall.

"It's hard to explain what's going on," manager Bruce Bochy said. "At this point, we'll take anything -- a blooper, anything to get us over the hump."

Mixing a 94 mph fastball with curves and changeups 15 mph slower, the 21-year-old Gallardo (1-0) silenced the Giants' sputtering offense and allowed just the one hit to Bonds from the second through the sixth inning until he began to tire.

Gallardo, considered one of the top prospects in baseball after amassing 188 strikeouts at two levels in the minors last season and 110 in 77 2/3 innings at Triple-A Nashville this year, gave up four hits and three walks while striking out four.

He gave up a homer to Pedro Feliz to lead off the seventh and make it 5-2, and after he was pulled, Ray Durham hit a two-run shot down the right-field line off reliever Carlos Villanueva to cut the Brewers' lead to 5-4.

In the ninth, Francisco Cordero loaded the bases with one out, but struck out Randy Winn swinging and induced Ryan Klesko to ground out for his 26th save in 28 chances. Milwaukee stretched its lead in the NL Central to seven games over the Chicago Cubs, who had the day off.

Bonds was left standing on deck to end the game. He didn't speak to the media before or afterward.

"We just couldn't pull it out," Klesko said. "That's the way it's kind of been going this last month, I guess."

Fielder, who hit an inside-the-park home run on Sunday in Minnesota, did it the conventional way with a two-run shot in the first to give the NL's best home team a 2-1 lead off Giants starter Noah Lowry.

Lowry (6-6) lasted 5 2/3 innings and gave up five runs on nine hits with three strikeouts and three walks.

Gallardo, who was born in Michoacan, Mexico, and moved to Fort Worth, Texas, when he was 4 years old, did his part at the plate. He lashed an RBI double in his first major league at-bat in the second to put the Brewers up 3-1.

"I was very excited about that. I love hitting. I just look at that as a bonus for a pitcher," said Gallardo, who had shaving cream in his right ear and his hair after the game. He is hitting .250 with a homer and three RBI in 24 at-bats this season in the minors.

Milwaukee tacked on runs in the fourth and fifth on a fielder's choice by Weeks and a solo homer by Corey Hart.

It looked like that would be more than enough for the right-hander, and that Bonds, who returned to the city where home run king Hank Aaron played 14 of his 23 years, would be only a subplot.

After Bonds' walk in the first, Bengie Molina followed with an RBI single to score Dave Roberts. But that was all the Giants could muster until Feliz's homer in the seventh.

Gallardo, pitching in place of injured Chris Capuano, then recorded an out before walking Kevin Frandsen and being pulled for Villanueva, who gave up the homer to Durham.

"That first inning, I was a little bit nervous," Gallardo said. "But I was able to settle down after that and just pitch the way I've been pitching and it worked out."

Notes

• Gallardo wore No. 49, the same number as fellow Mexican star Teddy Higuera, who won 94 games in a nine-year career with the Brewers. Gallardo said he didn't pick the number, but occasionally talks to Higuera on the phone.
• Molina took a foul ball from Braun off his right hand while catching in the third, but stayed in the game. X-rays were negative.
• Most of the 41,631 fans booed Bonds in each at-bat. It was the 11th sellout for Milwaukee this season.
• Brewers OF Tony Gwynn Jr. was optioned to Triple-A Nashville to get some more consistent work after batting .301 in 68 at-bats in Milwaukee.
• Giants INF Rich Aurilia (sore neck) was placed on the 15-day disabled list, C Eliezer Alfonzo was moved to the 60-day DL and INF Luis Figueroa was called up from Triple-A Fresno.