Kansas (29-2, 15-1 Big 12) led by 16 after a 20-4 run in the first half, then put together another 20-4 spurt after Morris' injury to beat its biggest rival for the eighth time in nine games. The Jayhawks shot 52 percent after a shaky start and will head into next week's Big 12 tournament as the No. 1 seed and one victory from joining Kentucky and North Carolina in the 2,000-win club.
Missouri (22-9, 10-6) struggled with Kansas' depth and size inside for the second time this season, giving up 42 points in the paint and 17 more rebounds in its final home game. Kim English had 16 points led the Tigers, who were 3 of 22 from 3-point range.
The Jayhawks wrapped up their sixth straight Big 12 regular-season title with an emotional win over rival Kansas State on Wednesday night in Collins' final game at Allen Fieldhouse.
That left the Jayhawks with two days to get ready for another rival.
Kansas manhandled Missouri the last meeting, holding the Tigers to 27 percent shooting and grabbing a 56-28 rebounding advantage in an 84-65 rout.
Back at home, where they were 16-1 this season, the Tigers seemed ready for Kansas.
Riding the emotion of Senior Day — J.T. Tiller, Zaire Taylor and Keith Ramsey were honored before the game — Missouri swarmed the Jayhawks early, getting them to force up shots against pressure and breaking out for easy baskets.
The euphoria didn't last long.
Working the ball inside, Kansas got six straight points from Markieff Morris, then seven straight from Marcus. The inside success opened up the outside and the Jayhawks started making shots from everywhere.
Collins put the finishing touches on a 20-4 half-closing run, scoring the final eight points to put the Jayhawks up 40-24.
Missouri still had some fight, using its defense to create turnovers and easy shots to open with a 16-4 run, pulling 44-40 on Tiller's three-point play on a hard drive.
It got worse for Kansas seconds later when Marcus Morris slammed his head on a courtside table while scrambling for a loose ball with Missouri's Marcus Denmon. Morris lay on the floor for several minutes then gingerly walked off the court to the locker room.
The Jayhawks rallied after seeing their teammate go down, reeling off another 20-4 run that included consecutive 3-pointers by Tyrel Reed. By the time Morris returned with just over 5 minutes left, Kansas was well in control.