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Derrick Williams nearly took his many skills to Memphis. Instead, the Pac-10's player of the year used them against the Tigers in the NCAA tournament.

Williams hit a late 3-pointer to finish with 22 points and 10 rebounds for Arizona, then blocked a potential tying shot in the final seconds to seal a 77-75 win on Friday.

"It's as if he's playing in his backyard," Wildcats coach Sean Miller said. "He just has a way of making big plays and finishing the other team off. He did it here again tonight."

Joe Jackson hit the first of two free throws with 5 seconds left, then missed the second to give the Tigers a shot at the tie. Wesley Witherspoon grabbed the offensive rebound at the right block, but Williams came over to swat it away and send the Wildcats into a Sunday game against fourth-seeded Texas in the West Region.

"At one point, he was wide open," Williams said. "I knew he wasn't going to shot fake it because there wasn't enough time on the clock, so I just went up trying to make a hard play on the ball like coach always tells us to do.

"Good thing it wasn't a foul."

Memphis coach Josh Pastner refused to protest that there wasn't a call and complimented Jim Burr — one of the referees who withdrew from the Big East tournament after missed calls cost Rutgers in a loss to St. John's — and the rest of the crew on a good game.

Pastner said he couldn't complain after his 12th-seeded Tigers (25-10) had a shot at the tie — even if Williams took it away, just as he did against Washington last month.

"Derrick's really good," Pastner said. "Like I've said, I voted for him for national player of the year. My vote doesn't change after today's performance because he's really good."

Lamont "MoMo" Jones added 18 points for Arizona (28-7), including the go-ahead 3-pointer with 1:35 to play. He added two free throws with 7.4 seconds left to make it a three-point game.

Antonio Barton scored 17 points and his brother Will Barton added 12 points for Memphis, which returned to the tournament after a one-year absence and played with its lowest seed ever. The Tigers won 13 NCAA tournament games over a four-year span under John Calipari, losing a late lead to Kansas in the 2008 national championship game.

"We're not some Cinderella story. I don't want us to be a Cinderella story," Pastner said. "My vision when I took the job — as I told our athletic director, R.C. Johnson — is we're trying to compete for national championships.

"We're not there yet, but we're going to get there."

Pastner was making his NCAA tournament coaching debut against the school where he was a longtime assistant to Lute Olson and a reserve on the Wildcats' 1997 championship team.

He also was close to attracting Williams, who visited only Memphis and Arizona after decommitting from Southern California following coach Tim Floyd's resignation.

Instead, he celebrated with Arizona after sending the Tigers home in his tournament debut.

Williams clenched his right fist and slapped his chest after blocking Witherspoon's putback try. The Tigers fouled Jamelle Horne with 0.4 seconds left, but there wasn't time for a tying shot even after he missed both ensuing free throws.

"He was tough and he did his thing," said Memphis' Will Coleman, who had nine points and 11 rebounds. "That's why he's nominated for player of the year. That's why he's up for it.

"He's a very good player, and he's not a lottery pick for no reason."

Arizona rallied from a 10-point deficit to lead 48-40 after Williams' three-point play completed a stretch of seven straight points in the first 2 minutes of the second half.

The Tigers, minus starters Tarik Black and Charles Carmouche with four fouls apiece, answered back by scoring 13 in a row. Antonio Barton hit a pair of 3-pointers during the surge, and Chris Crawford set up Will Coleman for a two-handed alley-oop jam that made it 53-48.

Arizona scored the next eight points, taking the lead back at 56-53 on a three-point play by Jordin Mayes — only to yield a 10-2 run by the Tigers and then come back with another eight straight points of its own.

And all that only set the table for a big finish.

Jones looked on as his 3-pointer from the right wing bounced around before finally falling through the net with 1:35 left, putting Arizona up 71-68 with 1:35 remaining.

Crawford missed a 3-pointer at the other end, one of the rare times it seemed evident that Memphis — with seven freshmen — was the youngest team to make the 68-team bracket. Mayes got fouled on a drive to the basket and hit two free throws to push Arizona's lead to five.

The Tigers, who had won 12 of their previous 13 games decided by four points or less, made it interesting when Will Barton stole an inbounds pass and missed a tying 3-pointer with 15 seconds left. Jackson put back his miss to get Memphis within one with 12.8 seconds left.

"We've been in this situation plenty of times this year. We've been down in the last second and we've pulled through," Antonio Barton said. "When we get down like this, we're not panicking or anything. We just always have hope that we're going to pull the game out."