Bruce Stevens scored 22 points, Burnett added 20, and Mississippi held off Florida for a 78-72 win on Saturday afternoon.
Burnett - a transfer from the University of Miami - added six assists and two rebounds. It was his first game back after sitting out against No. 22 Auburn last Tuesday after a bout with the flu.
"It's very big being from Florida and beating a team like Florida," Burnett said. "I felt great. The win helped me pushed through. My teammates behind me and us staying together just got us a real gutsy win down the stretch."
The Rebels (10-7, 3-2 Southeastern Conference) used success in the paint and on the boards to hand the Gators their first conference loss of the season.
Ole Miss shot 41 percent from the floor, including 15 of 25 in the second half, outscored the Gators 32-22 in the paint, and outrebounded them 44-35. After shooting 30 percent in the first half, the Rebels doubled it with a 60 percent effort in the second.
"I think our ball movement was a little bit better," Ole Miss coach Andy Kennedy said. "We were still trying to go through Bruce (Stevens) because Bruce had 10 or 12 (points) at the half. We were trying to make a concerted effort of throwing it close and don't settle. In the second half, quite frankly, we just made more shots."
Burnett scored 15 of his points in the second half, shooting 4 of 4 from the field, including 2 of 2 from 3-point range.
Keith Stone scored 23 points on 4-of-10 shooting from the floor and 13-of-18 from the free-throw line for Florida (12-5, 4-1). Jalen Hudson and Egor Koulechov scored 11 points apiece, with Koulechov grabbing 11 rebounds.
"Both teams battled. I thought Ole Miss battled a little harder," Florida coach Michael White said. "They won the majority of the 50-50 balls in my opinion, especially in the second half. They wanted it a little more."
It is the first time the Rebels have beaten Florida since White - a former Ole Miss player - took over, replacing Billy Donavan in 2015.
Florida: Coming off their first conference loss of the season, the Gators control their own destiny sitting atop the SEC standings. Next week will be a key stretch.
Mississippi: After blowing at 10-point halftime lead at No. 22 Auburn, Saturday's win was much-needed for the Rebels' postseason chances.
With the game tied at 60, the Gators went 2 of 13 in the final 7:49 of the game while Ole Miss went 4 of 6 during that same stretch.
Florida: The Gators return home to host Arkansas on Wednesday before traveling to play No. 21 Kentucky next Saturday.
Mississippi: The Rebels begin a two-game road trip on Tuesday, playing at Texas A&M on Tuesday and traveling to Arkansas next Saturday.
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