Colin Castleton is accustomed to being double-teamed every time he touches the ball, so he was pleasantly surprised -- maybe even downright stunned -- when Tennessee opted to guard him with a single defender in the second half.
"I've got to take advantage of that," Castleton said.
He did.
Castleton scored a game-high 20 points, including 16 in the second half, and Florida upended the second-ranked Volunteers 67-54 on Wednesday night.
Kyle Lofton added 14 points for the Gators, who delivered coach Todd Golden his most significant victory in his first season in Gainesville. It was Florida's second Quadrant 1 win in the past two weeks.
The Volunteers, playing with their highest ranking in four years, lost for the first time in five games. They had won nine of 10.
They became the 10th different AP top-two school to lose a game this season, snapping a tie with the 1982-83 and 2002-03 seasons for the most such teams to lose while in the top two in AP Poll history
"Our guys are disappointed," Tennessee coach Rick Barnes said. "We're better than this, but tonight we weren't."
Tennessee (18-4, 7-2 SEC) looked like it had taken control midway through the second half. It outscored Florida by 10 points in the early going to take a six-point lead.
But the Gators (13-9, 6-3) stormed back behind Castleton, who scored 11 of 14 points as Florida rallied. The senior had a dunk, two free throws, a three-point play, a layup and a short jumper -- essentially putting the team on his back down the stretch.
"They went small, and I felt like I had a mismatch," Castleton said.
Myreon Jones and Will Richard chipped in nine points apiece for the Gators.
Zakai Zeigler led the Vols with 15 points on 6-of-19 shooting. Olivier Nkamhoua added 11 points and nine rebounds for the visitors, who also got 11 points and eight boards from Santiago Vescovi.
The Gators were red hot to start the game, making six of their first eight shots -- including all three from 3-point range -- while building a 17-4 advantage. But they quickly cooled against the nation's best defense, missing nine of their next 11 as Tennessee cut it to 22-21.
The Vols had it going coming out of the locker room, with Zeigler getting into the paint and making things happen. But it was short-lived, thanks mostly to Castleton.
"We gave them a chance to start believing in what they're doing, and they took it," Barnes said.
Information from ESPN Stats & Information and The Associated Press was used in this report.