No. 12 Kentucky (24-7, 10-6 SEC) got 14 points from Bria Goss and 12 points apiece from DeNesha Stallworth and Linnae Harper to avenge a pair of double-digit losses to South Carolina (27-4, 14-2 SEC) this season.
Tiffany Mitchell to just 11 points on 4-of-12 shooting.
Kentucky will be seeking its first SEC tourney championship since 1982. The Cats lost to Texas A&M in last year's finals and to Tennessee in both 2010 and 2011.
"I'm really, really happy about today," Mitchell said. "But I do want to stay focused on what we came down here to do, and that's to win the championship.
"I would really be happy for them if they can prepare and finish the job tomorrow."
No. 6 Tennessee (26-5, 13-3 SEC) advanced with an 86-77 win over No. 15 Texas A&M on Saturday. UK defeated the Lady Vols 75-71 on Feb. 16 in Knoxville, the only regular-season matchup between the teams this season.