The Gamecocks (20-2, 8-1 Southeastern Conference) won their fourth consecutive game and moved into first place as the only one-loss SEC team after No. 16 Vanderbilt defeated 17th-ranked Texas A&M earlier in the day. South Carolina and the Aggies had been tied for the top.
Missouri (14-8, 3-6) cut a 23-point halftime deficit to 73-60 in the final two minutes. But South Carolina proved too tall, too strong and too fast to overcome.
The Gamecocks 6-foot-4 forwards in Alaina Coates and Elem Ibiam combined for 23 points, 11 rebounds and seven blocks. And the strong performance all took place with the nation's top recruit, Columbia's A'ja Wilson watching with her family behind the bench.
Bri Kulas has 21 points to lead the Tigers.
The Gamecocks finished with six players in double figures for a second straight game. Khadijah Sessions and Coates had 13 points each, Aleighsa Welch and Asia Dozier 11 apiece and Ibiam 10.
Missouri has lost five of its past six, four of those to ranked SEC opponents.
It was just the fifth time in 23 SEC seasons that South Carolina has posted 20 wins. This is the Gamecocks best SEC start ever and matches the 8-1 school record mark they posted in the defunct Metro Conference in 1987-88.
South Carolina has rebounded strongly from its lone SEC loss at Texas A&M with three straight victories including a 99-70 win over Ole Miss this Thursday. Like that last game, South Carolina used a late charge in the opening half to take control.
The Gamecocks used a 19-1 the final seven minutes or so to put away the Rebels. This time, it was a 23-6 run over the final 6:03 to take a 48-25 lead into the locker room.
Sessions scored all nine of her points, while the 6-4 Coates added four.
South Carolina made Kulas, the SEC's second-leading scorer at 18.6 points a game coming in, work for her points. Sessions and Tiffany Mitchell chased Kulas all over the court in the first 20 minutes.
Kulas finished 8 of 17 from the floor with three 3-pointers and 10 rebounds
The Tigers made run at the start of the second half, outscoring South Carolina 15-5 to cut the lead to 53-40 on Kulas' three-point play with 13:03 left. But Coates followed with an inside bucket, Mitchell hit a 3-pointer and South Carolina pushed its lead back over 20 points.
This game was also about wooing the 6-4 Wilscon to the Gamecocks, one of her four finalists along with powerhouses Connecticut, Tennessee and North Carolina.
Wilson, who played for Heathwood Hall High a few miles from campus, sat with her parents sat behind the South Carolina bench. Fans wore neon lime give-away shirts with "There's No Place Like Home" on the front. There was a first-half video featuring football coach Steve Spurrier, baseball coach Chad Holbrook and Staley, all using "The Wizard of Oz" movie's most famous line.
Fans began "We Want A'ja" chants and an oversized poster of Wilson's face was held up in the student section.
Wilson is expected to make her choice sometime after her season ends.