It was the first home win for the Gamecocks (14-8, 6-5 Southeastern Conference) over the Wildcats (19-3, 10-1) since 1997, and it was just South Carolina's sixth victory in 41 meetings against Kentucky, which never looked in synch.
Fans poured onto the court after the victory, arguably South Carolina's best in coach Dave Odom's tenure, and Kinsey stood on press row, slapping high-fives with celebrating students.
The Wildcats, who had won 19 straight games against SEC opponents, had a season-high 21 turnovers and Chuck Hayes was held to just one point. Kelenna Azubuike led Kentucky with 16 points - five in the second half.
The near capacity crowd finally had something to cheer about after the Gamecocks' disappointing 74-71 home loss to Auburn on Saturday. South Carolina added a high-profile win as it attempts to build its NCAA tournament resume. The Gamecocks were 0-4 against ranked opponents coming into Tuesday's matchup, but they still have a game against No. 18 Alabama.
South Carolina built a 58-45 lead with 4:16 left after an 8-0 run and the Wildcats never seriously threatened again. The run featured a three-point play and dunk from Carlos Powell, the Gamecocks' leading scorer who had been held to just two points in the first half.
But South Carolina pounded the ball inside to Powell and Kentucky had no answer.
The Gamecocks had built a 12-point lead on some key long-range shooting by Kinsey, who was averaging 9.5 points a game. His fourth 3 of the game, a career-high, brought the crowd to its feet midway through the second half. Kinsey finished with five 3s, a career-high.
On the next trip down, he missed a 3, but Antoine Tisby followed with a dunk to cap a 13-2 run with 13:28 left in the first half.
It was Tisby's best game of the season. He had played just 8 minutes in the past five games, and didn't even make the trip to South Carolina's Jan. 29 game at Florida.
Kentucky couldn't make any key shots to get a run going in the second half, and could have been hung over from a sluggish nine-point win against Georgia over the weekend, after which coach Tubby Smith told his team he was ashamed of them.
Kentucky cut the lead to six with 10 minutes to go, but Rocky Trice's layup with 8:15 to go gave the Gamecocks a 48-38 lead.
Kentucky had 11 turnovers in the first half, which is just shy of the Wildcats' 12.9 average per game. They shot just 40 percent (8-for-20) from the field.
Smith tried to find a spark by benching his starters, which he did against Georgia last Saturday, but he didn't get the boost the Wildcats needed. Azubuike had 11 points in the first half, but Hayes was held to just a free throw.
The Gamecocks weren't much better, even though they led 25-23 at halftime. South Carolina shot 36.7 percent (11-for-30) from the field, including 2-of-10 on 3-pointers.