Carlos Beltran limped to the trainer's room, taking the St. Louis Cardinals' biggest clutch October bat with him. Beltran strained his left knee running out a double-play ball in the first and the Cardinals said he was day to day.

Turns out they had the perfect substitute.

Carpenter followed Jon Jay's two-out single with a homer off Cain in his first at-bat of the NLCS.

Beltran is batting .400 in the postseason with three homers and six RBIs, but Carpenter had big numbers against Cain. He was 4 for 4 for his career against Cain, all four of the regular-season hits for singles.

This one was a much bigger deal, a drive on a 2-2 count that soared over the Cardinals bullpen in right field and was estimated at 421 feet.

Carpenter entered the game 1 for 5 in the postseason, all five pinch-hit appearances. He had an RBI single in the wild-card playoff against Atlanta. He got 14 of his 46 RBIs in April as the primary sub at first base for injured Lance Berkman.

On Tuesday, Carpenter was among a group of seldom-used hitters trying to stay sharp by facing Jake Westbrook in a simulated game. The rest of the team had the day off.

Umpires called for the tarpaulin right after the Cardinals made it 3-1 on a run-scoring single by Shane Robinson and Cain was lifted.

It was the third game delayed by rain this postseason and a fourth, Game 4 of the Yankees-Tigers ALCS, was postponed later Wednesday night. Two games between the Yankees and Orioles in Baltimore began late because of inclement weather.

The rain intensified less than 10 minutes after the field was covered, chasing most fans who had remained in their seats up to that point. Spotters for the National Weather Service reported 60 mph winds in nearby St. Charles County.

A highlight of the delay was a Pac-Man style chase. Ushers pursued and finally apprehended a fan who jumped out of the stands to get a baseball near the warning track in left field, and then jutted in and out of aisles to elude several ushers who had been closing in.

The storm had been widely anticipated. Some forecasts called for a 70 percent chance of rain. Both managers fielded questions Tuesday and Wednesday about whether the probability of precipitation would affect their selection of the starting pitcher.

Both said they couldn't worry about the weather, and the starters combined for 208 pitches.

"I've been caught before where you try to predict what's going to happen with the rain and started," Bochy said. "Just a couple years ago I started a pitcher thinking the same thing and it didn't rain for four or five innings. Then I put my starter in and then it started raining, and so it came back to bite me."

Lohse is 2-1 with a 1.96 ERA this postseason despite uncustomary control woes. He was among the majors' best control pitchers this season, averaging 1.62 walks per nine innings.

The Giants entered 70-22 when scoring first, including the postseason, and took the lead in the third on Pablo Sandoval's run-scoring groundout after leadoff hits by Angel Pagan and Scutaro, whose legs looked just fine on an opposite-field double flared just over first baseman Allen Craig's glove.

Beltran leads all players with eight extra-base hits in the 2012 playoffs and is a career .375 hitter in the postseason, highest ever among players with a minimum of 100 at-bats.

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Cardinals Beat Giants, Take 2-1 Series Lead