DALLAS -- Steve Kerr was a forgotten man for most of the postseason.

''I'm 37. I'm slow. I'm not a very good defender,'' Kerr said, explaining why San Antonio coach Gregg Popovich had kept him at the end of the bench.

Kerr went into Game 6 of the Western Conference finals having played just 13 minutes with a grand total of zero field goals.

But in the third quarter Thursday night, Popovich had nothing to lose. His team was playing poorly, his starting point guard was ill and the backup wasn't effective. So he turned to the guy with four NBA championship rings and told him to fire away.

Rekindling images of his glory days alongside Michael Jordan in Chicago, Kerr hit four 3-pointers, three during an amazing fourth-quarter rally that took the Spurs from 13 down all the way to the NBA Finals.

San Antonio beat the Dallas Mavericks 90-78 to win the series 4-2. The Spurs advanced to play the New Jersey Nets in the championship round, starting at home Wednesday night.

''I mentioned to Steve that he needed to be ready tonight, and he was real ready,'' Popovich said. ''It's a fitting finish to what I thought would be the end of his career, but he told me we're going to have to think about an extension or he won't be available for the finals. And he said that with a straight face.''

Dallas led by as many as 15 and was ahead 71-58 when Nick Van Exel made a jumper with 10:53 left. Even with Dirk Nowitzki missing a third straight game because of a sprained left knee, the Mavericks appeared headed to a winner-take-all seventh game on Saturday night in San Antonio.

''I didn't think the game was over,'' Mavs guard Raja Bell said, ''but you can't help thinking about Game 7.''

The Spurs came back with stingy defense and the outside shooting they lacked in previous games. Their six straight 3-pointers to open the fourth quarter were the ultimate zone-busters.

Manu Ginobili had the first, then Stephen Jackson hit two. Kerr's trio came in a span of four possessions, with the first tying it at 71 and the last making it 79-71. Ginobili added two free throws before Van Exel ended Dallas' drought with 2:51 left.

Over 8:02, the Mavericks missed seven shots and committed six turnovers. It was a stunning meltdown for a team that has thrived on making other teams melt down, such as in Game 5, when they made San Antonio blow a 19-point lead.

''We were playing so well for so long and the bottom just dropped out,'' coach Don Nelson said. ''We couldn't get a shot to go in. We went cold at the wrong time.''

Nelson, only under contract as general manager next season, might've been on the sideline for the final time.

Kerr, the career leader in 3-point accuracy, took only four shots, but made them all, and all were behind the line. That made for 12 points in 13 minutes. He also had three assists and two rebounds.

''I figured just let it fly and see what happens,'' said Kerr, who won three NBA titles with Chicago and one with the Spurs in 1999. ''This is one of best nights of my career, ranks right up there with anything that happened in Chicago.''

Jackson scored 24 points, making five of San Antonio's 10 3-pointers.

, on a night when Tim Duncan was constantly double- and triple-teamed.

Duncan had 18 points and 11 rebounds, Rose had 12 and Ginobili added 11 to help San Antonio overcome scoreless outings from two starters -- Tony Parker and Bruce Bowen.

Van Exel had 19 points to lead the Mavericks, who were without Nowitzki for the third straight game because of a knee injury that probably would've prevented him from playing in a Game 7.

Michael Finley, who had only 13 points after 31 the previous game, bit his collar as he left the court with 1:01 to play, then hugged Nelson.

When the game ended, a franchise-record crowd of 20,812 stood and applauded. Steve Nash, the last player to leave the court, slowly made a 360-degree turn while returning the applause.

''We have a lot to be proud of,'' said Nash, who had six points and 11 assists. ''At the same time, we didn't reach our goal, so it hurts.''