San Francisco ? As a young player, Benito Santiago had his share of long hitting streaks and memorable home runs.

But in 17 years in the majors, there’s been nothing like this not even close. Never did all his impressive numbers get him so far.

San Francisco’s veteran catcher is a postseason star at age 37. His sensational season seems to get better with every big hit.

He hit a tiebreaking, two-run homer with two outs in the eighth inning as the Giants beat the St. Louis Cardinals, 4-3, Sunday night in Game 4 of the NL championship series.

That’s two huge hits for Santiago in this series.

“I don’t know how to describe it. It’s unbelievable,” Santiago said as a slew of friends and strangers congratulated him.

A handful of Giants faithful remained in the stands next to the San Francisco dugout after the game, and chanted “Ben-i-to! Ben-i-to!” as he walked by.

Santiago sure enjoys the opportunity he has to do damage batting behind Barry Bonds, and he is making the most of it.

His late-game power helped San Francisco take a 3-1 lead in the series and move within a game of the franchise’s first World Series since 1989. The Giants can finish off the Cardinals tonight at Pacific Bell Park, avoiding a return trip to Busch Stadium in St. Louis.

San Francisco's Benito Santiago (33) celebrates with teammates J.T. Snow, left, and Barry Bonds, right, after Santiago hit a two-run home run. The Giants downed St. Louis, 4-3, in Game 4 of the NL championship series Sunday in San Francisco.

San Francisco lefty Kirk Rueter takes the mound against Matt Morris.

Santiago, an All-Star this season for the first time in 10 years, is batting .353 in the NLCS, second on the team only to David Bell’s .385.

With Bonds aboard on an intentional walk, Santiago hit a 3-2 pitch from Rick White into the bleachers in left field, a shot that sent the 42,676 fans into an absolute frenzy.

“You know what, I like to see these people rockin’ the house like that,” he said. “I was looking for that type of pitch. He got me out with that pitch. I guessed right this time.”

He made up for a strikeout with two runners on in the sixth inning, in which he looked at three called strikes.

On Wednesday, Santiago drove in four runs, including three after walks to Bonds, as the Giants won Game 1 at Busch Stadium, 9-6.

The scene was quite similar Sunday. The Giants tied it 2-all with two runs in the sixth and were just waiting for someone to get the big hit.

“I was so excited they walked Barry Bonds,” Santiago said. “I wanted to make them pay again.”

Santiago didn’t hide his emotions one bit after his homer either. He’s having the time of his life and feels about 10 years younger than he really is.

After his drive sailed into the seats, he threw his bat to the ground with authority and rounded the bases.

“I hit it hard,” Santiago said. “But I wanted to see it go out.”

After 17 seasons in the majors, Santiago sure isn’t slowing down and he has no plans to do so. He feels like he’s definitely playing some of the best baseball of his career.

“I’ve been saying it since last year. What he does is unbelievable,” pitcher Jason Schmidt said. “He’s a motivator. He motivates the pitchers. You’ve got to have that on a team like this. He’s living for the moment.”