SAN JUAN, Puerto Rico (Ticker) -- A.J. Pierzynski's grand slam with two outs in the top of the 11th inning lifted the San Francisco Giants to a 7-2 victory over the Montreal Expos .

Pierzynski recorded his third career grand slam and finished with six RBI - one shy of his career high. He also recorded his second three-hit game of the season, hit his first grand slam since June 12 vs. Colorado and atoned for an earlier baserunning mistake.

"In my first at-bat, I hit the ball good but it didn't go anywhere and I was frustrated," Pierzynski said. "On my second at-bat, I hit the ball good again and when it went to the gap, that scored two. The last at-bat, he didn't (want to) pitch me. When the curve came after the 2-1 count, the wind goes to right field and I tried to pull the ball there."

The Giants took a 3-2 lead against Jeremy Fikac (0-1) on a grounder by slugger Barry Bonds that plated Michael Tucker . With the infield playing back, second baseman Jose Vidro tried for the play at the plate but Tucker beat the throw.

After Pedro Feliz lined out to third, Pierzynski drove Fikac's 1-0 pitch into the right field seats.

In addition to his second homer of the season, Pierzynski had a two-run double in the fourth inning that staked the Giants to a 2-1 lead.

The Giants won their third in a row and second straight in extra innings. On Thursday, Neifi Perez homered off Chicago Cubs closer Joe Borowski in the top of the 10th inning.

"I think the whole team is frustrated," Pierzynski said. "We have to work and try to find the way to stay positive. That is not easy to do, but we have to find the way to do it. This is the reason that we feel good to win this game."

Before Pierzynski homered, San Francisco had a chance to go ahead in the ninth when Bonds came up with the bases loaded. But after Fikac got ahead of him, Bonds flied out to the warning track in left.

After San Francisco starter Jerome Williams went seven innings, four relievers combined to allow three hits the rest of the way. Tyler Walker (3-0) pitched two innings for the win.

Montreal starter Claudio Vargas also pitched well, allowing two runs and four hits in seven innings.

The Expos dropped their fourth in a row and fell to 2-9 at Hiram Bithorn Stadium. They stranded 10 runners and missed a chance for the win in the 10th when San Francisco manager Felipe Alou opted to walk rookie Terrmel Sledge .

But the move proved correct as Walker got Juan Rivera to bounce into an inning-ending double play.

"It is a frustration," Montreal manager Frank Robinson said. "We know we have to do little things to win."

Bonds finished 0-for-3 and the fans rose to their feet each time he came up. His biggest contribution was a solid defensive play in the fourth when he threw out Orlando Cabrera at the plate.

"I lived in this area," Alou said. "That's just the way the fans are. This is very common for Latin American fans."

In a game that featured a pair of short rain delays, Montreal took a 1-0 lead on Tony Batista 's base hit in the second. After Brad Wilkerson 's sacrifice fly tied it in the fifth, the Expos managed just two hits and hit into a pair of inning-ending double plays.