AUBURN HILLS, Mich. — The Jazz beat Detroit on Saturday night, but a rookie mistake made by — appropriately enough — a rookie almost prevented the overtime victory.

With 21.1 seconds remaining in regulation and the game tied at 80, and after Detroit had missed two shots earlier on the same possession, rookie point guard Deron Williams fouled Pistons point Chauncey Billups.

No one knew why at the time, though Williams explained afterward.

"I thought it was 81-80," Williams said. "I looked over (at the Jazz bench) and saw (coach) Jerry (Sloan) jumping up and down, and I thought he was wanting me to foul. I guess he was just jumping because he was mad."

Billups wound up making both free throws, and the Jazz forced overtime only because Andrei Kirilenko knocked down two freebies of his own with 15.6 seconds left in the fourth quarter.

Williams, the No. 3 overall selection in last June's NBA draft, said he realized his blunder "as soon as I looked up" at the scoreboard.

"He made a mistake. He knows it," Sloan said. "That's what rookies do. He hasn't been out there in situations like that a lot."

TOUCHE: Because the Jazz eventually won in OT Saturday, Williams took some good-natured kidding about his miscue.

That wasn't the only grief he got Saturday.

Teammates, including Matt Harpring, made note of the fact that Williams' former University of Illinois team had lost earlier in the day to Iowa.

Williams' response?

"I said, 'Where's Georgia Tech at?' " he said. "We're 15-1. That's not bad."

HOME CROWD: The 26-5 Pistons had their 101st consecutive sellout Saturday at The Palace of Auburn Hills, a fact not lost on the Jazz.

"Detroit won the championship two years ago," Kirilenko said. "They're really playing like champions right now. They play like a team, sell out every game, and the crowd really gets into it.

"That," Kirilenko added after the Jazz became the only team so far this season to beat Detroit twice, "just motivates us more."

SILLYPUTTY: Jazz center Greg Ostertag had his best game in quite some time, pulling down nine rebounds, scoring nine points and blocking three shots in 31 off-the-bench minutes — the longest stint he's had since Nov. 7.

"Greg," Sloan said, "plays alive when he puts his mind to basketball — and not all the silly stuff he does."

THEY STILL LOVE HIM: Ex-Pistons big man Mehmet Okur, a member of Detroit's most-recent title team, had a 17-rebound, 13-point effort against his old club — his 11th 10-plus boards outing in the last 14 games, and his team-leading 14th double-double of the season.

Okur got a rousing round of applause during pregame introductions.

MISC.: Harpring played in the back half of a back-to-back set despite his surgically repaired right knee — he is now medically cleared to do that — and finished with 12 points off the bench . . . Healthy rookie shooting guard Andre Owens again was inactive for the Jazz, and forward Kris Humphries dressed but did not play . . . Former Jazz point guard Carlos Arroyo got off five shots while playing just seven minutes off the bench, and finished with four points.