Ole Miss had the ball trailing 51-50 in the final moments, but Kendrick Fox missed a 3-pointer with 19 seconds to play and Kentucky's Patrick Sparks hit two free throws to extend the Wildcats' lead to three.
Londrick Nolen's desperation 3-pointer at the buzzer bounced harmlessly off the back iron, giving the Wildcats their second big come-from-behind victory of the season and ninth victory in 10 games.
Kentucky took its first lead of the game when Rondo's three-point play made it 49-48 with 3:02 remaining. That came as part of an 11-2 run which pushed the Wildcats' lead to three.
Kentucky opened the second half with 10 straight points and pulled to within 31-29 with 14:02 remaining.
Tommie Eddie had 12 of his 14 points in the second half, and Nolen added 12 for the Rebels (11-7, 2-3), who in the first half successfully lulled the Wildcats into a grind-it-out game.
Kentucky went scoreless over the first six minutes, started just 1-of-11 from the floor and shot just 20 percent in tying their least productive first half of the season.
Ole Miss' largest lead was 29-14 on Todd Abernethy's three-point play with 15.4 seconds left in the half.
Kentucky's 16 points and 5-for-24 shooting at halftime matched season lows set in December against Louisville. The Wildcats rallied from a 16-point halftime deficit to beat the Cardinals 60-58.
Kentucky improved its edge in the series with Ole Miss to a remarkable 92-10, and has won five straight against the Rebels.
The Wildcats played without freshman Joe Crawford, who didn't make the trip to Oxford. He returned to the team Monday after spending a week at home after a dispute over playing time.
The game also was something of a family reunion for Tubby Smith. His son, Brian, is a reserve guard for the Rebels who did not play against the Wildcats but with the two met near midcourt before the game.