SAN FRANCISCO -- Barry Bonds strolled to the plate and St. Louis manager Tony La Russa never hesitated, putting four fingers in the air for an intentional walk.

It seemed like a good idea -- until catcher Benito Santiago connected.

Santiago followed the walk with a tiebreaking two-run homer with two outs in the eighth inning, leading the San Francisco Giants to a 4-3 victory over the St. Louis Cardinals on Sunday night in Game 4 of the NL championship series.

Bonds, who scored the tying and go-ahead runs, is now one win away from his first trip to the World Series.

Robb Nen nearly blew it in the ninth, throwing a third-strike wild pitch to the leadoff hitter and allowing a one-out RBI single by Jim Edmonds.

But with runners on first and third, Nen recovered to strike out Albert Pujols and J.D. Drew for his third save in the series.

The Giants can win their first NL pennant in 13 years with a win at home tonight and set up baseball's first all wild-card World Series. Anaheim clinched the AL championship earlier Sunday.

Game 1 winner Kirk Rueter with pitch the fifth game for the Giants against Matt Morris.

With two outs and nobody on in the eighth, Bonds stepped to the plate. Left-handed specialist Steve Kline was ready in the bullpen, but La Russa decided to stay with righty Rick White and walk Bonds intentionally.

That brought up Santiago, who was nearly out of baseball after a life-threatening car accident in 1998. With a sellout crowd of 42,676 pounding their orange ThunderStix, Santiago worked the count full.

He then drove a pitch into the left-field seats. Santiago pumped his fist and tossed his bat away before rounding the bases. Bonds pumped his fist repeatedly on his way home -- his long wait for a chance to perform on baseball's biggest stage just one game away.

Bonds had never won a postseason series before this season, losing all five tries -- partly because of his own struggles. He hit .196 with one home run and six RBIs in 97 at-bats in his first five postseason trips, hardly the numbers of baseball's best player.

This season, he has risen to the occasion with four homers and nine RBIs in October. But his threat proved to be the biggest contribution of all, setting up the game-winning hit.

Tim Worrell got the final two outs of the eighth for the win.

Giants starter Livan Hernandez, who brought a 6-0 career postseason record and boasts of his perfection into the game, gave up two runs in the first but held the Cardinals at bay after that.

He was relieved by Felix Rodriguez with one out in the sixth and a runner on second base. Rodriguez retired Edmonds on a grounder and Pujols on a flyout, preserving the tie and Hernandez's perfect record.

Cardinals starter Andy Benes, who was pitching underhanded to kindergartners in June as he contemplated retirement, shut out Bonds and the Giants on two hits through five innings.

La Russa let Benes bat with two on and two outs in the top of the sixth and the pitcher grounded out.

The decision proved costly. Benes walked Jeff Kent with one out before throwing four straight balls to Bonds -- none even close to the strike zone.

La Russa then pulled Benes for Rick White, who struck out Santiago. J.T. Snow then hit a 1-0 pitch off the wall in left-center for a two-run double and Bonds stomped on home plate as he scored the tying run.

The Cardinals broke out on top for the first time this series.

Fernando Vina hit the first pitch of the game into the gap in left-center for a double. Vina later scored on Edmonds' one-out grounder, but Hernandez got in trouble when he hit Pujols in the back with a pitch.

Pujols glared out at the mound -- but no one left the dugout, as in Game 1. St. Louis made the Giants pay when Drew followed with a single and Tino Martinez blooped another single down the left-field line for his first RBI of the postseason.

Hernandez pitched out of trouble after that, holding the Cardinals to one hit in nine at-bats with runners in scoring position.

Once again, 5-year-old Kannon Kile romped around the dugout during the game. The son of late St. Louis pitcher Darryl Kile has been a source of motivation to the team during the two games in San Francisco.