SAN FRANCISCO, OCT. 9 -- Jim Lindeman spent most of this season laying on a bad back. But tonight, filling in for the injured Cardinals slugger Jack Clark, the rookie first baseman showed he is strong enough to carry a team.

Lindeman's homer to right-center in the sixth inning, with Ozzie Smith on first and the Cardinals down, 4-0, silenced a roaring crowd at Candlestick Park. One inning later, he drove in another run with a sacrifice fly during a four-run rally that finished off the San Francisco Giants.

"It's the greatest thing that's happened to me in major league ball," said Lindeman, who played in only 75 games this year because of back spasms that put him on the disabled list twice. "A timely home run every now and then is something we have to look for."

For the second time in three championship series games, the Cardinals took advantage of their injuries to win. In the opening game of this series, scheduled Cardinals starter Danny Cox developed a stiff neck. Greg Mathews, one of the Cardinals' most ordinary pitchers, came in to stuff the Giants, 5-3.

Tonight, it was Lindeman's turn. Because of an injured right ankle which has kept Clark, the Cardinals' power hitter, out of action for nearly a month, Lindeman was put in the cleanup spot.

"I think the last time I batted cleanup I probably went oh for four and broke three bats," joked Lindeman after the game.

The Cardinals' other hero last night was left fielder Vince Coleman. His single up the middle in the four-run seventh scored pinch runner Lance Johnson and Curt Ford, another backup who had pinch hit for a single.

The last time Coleman was in a league championship, he nearly lost his legs. In 1985 against Los Angeles, he missed the last three games of the series after being trapped under an automatic tarp.

Most of the Cardinals' heroes last night were second stringers. Besides Lindeman, Ford and Johnson, there was Dan Driessen, another first baseman who drove in a run in the seventh with a pinch hit single. He is a former Giant, released in May of last year. He is also the only player in this series who is being paid by both teams. When he was released, the Giants bought out his contract. He will be getting deferred payments until the year 2000.

Along with the paychecks, the Giants may be sending a get-well card to Jack Clark.