ROSEMONT, Illinois (Ticker) -- Deron Williams' play on both sides of the 3-point line sent Illinois on a trip to St. Louis.
Williams hit four 3-pointers in the final nine minutes as the top seed Fighting Illini rallied from its largest deficit of the season for a 90-89 overtime victory over third-seeded Arizona in the final of the Chicago Region.
"I knew I had to step it up for our team and try to take control," Williams said. "Down the stretch I just got aggressive and started shooting the ball when I had the shot."
With the miraculous win, Illinois (36-1) advanced to its first Final Foul since 1989, setting up a national semifinal matchup with Louisville.
"You can see why they are 36-1, they are not a team that will ever give up," Arizona coach Lute Olson said.
It was sweet revenge for the Fighting Illini, who fell as a top seed in their last trip to the regional finals to the Wildcats in 2001.
Coming back from a 75-60 deficit with 4:02 remaining, Williams hit two 3-pointers during a 20-5 run, including the tying basket with 31 seconds remaining. Previously, Illinois trailed Purdue by nine points before rallying for a 68-59 victory on January 8.
"What an unbelievable game tonight, our kids didn't quit," Illinois coach Bruce Weber said. "We made some big shots to get back in the game, to force overtime and we made some big shots in overtime."
After Arizona (30-7) missed two attempts from the arc in the closing seconds of regulation, Williams opened the overtime with a 3-pointer, Roger Powell made a layup and Williams knocked down another deep shot to give Illinois an 88-84 lead with 2:22 to play. Luther Head followed with a steal and a layup 20 seconds later to push the cushion to six points.
"Down the stretch we made a number of mistakes not coming to the ball hard enough," Olson said. "They got interceptions on us and they knocked down a number of three's under the most extreme pressure they could."
Hassan Adams' three-point play and layup off an offensive rebound cut Arizona's deficit to 90-89 with 53 seconds left, but he missed a 3-pointer in the closing seconds as the Wildcats looked unprepared for the final possession.
Salim Stoudamire, the Wildcats' leading scorer who hit a pull-up 15-footer with 2.8 seconds left in a 79-78 triumph over No. 2 Oklahoma State in the regional semifinal on Thursday, did not touch the ball on the final play.
"No it wasn't (designed for me)," Stoudamire said. "I just came over (to Adams) because he looked at me like he wanted to give me the ball."
Williams, who scored 22 points and handed out nine assists, played a key role on the defensive end in shutting down the Pac-10's all-time leader in 3-pointers. His tough man-to-man defense limited Stoudamire to just nine points on 2-of-13 shooting, including 1-of-7 from the arc.
"I thought Williams did a great job on (Salim)," Olson said. "He made it difficult for him tonight."
With Arizona leading, 62-58, with about 8 1/2 minutes to play, Adams made a fast-break layup, Mustafa Shakur hit a shot from the arc and Channing Frye knocked down just his third 3-pointer of the season during a 13-2 run that gave the Wildcats their 15-point advantage.
Head scored 20 points, Powell added 16 and Brown 15 for Illinois, which shot 53 percent (18-of-34) after intermission.
Frye had 24 points and 10 rebounds and Adams added 21 and 10 for the Wildcats, who lost despite holding a 44-24 advantage in points in the paint.
Combined with the loss of the sizeable lead, Frye and Stoudamire ended their collegiate career as the first senior class at Arizona in 12 years to not make the Final Four.