Baylor clawed within 59-49 on a pair of Jackson free throws and a bucket by Taurean Prince.
Omari Lawrence converted a three-point play, Henriquez scored down low, and after Austin sank a pair of free throws, Rodriguez hit McGruder for an alley-oop.
A 3 by Austin brought the Bears within 12, but a three-point play by Rodriguez and a second-chance bucket by McGruder opened the gap to 71-54 with 4:03 to play.
Baylor did not get within single the rest of the game.
Early in the first half, Baylor dominated the paint, and Kansas State lived in 3-point range.
McGruder sparked the Wildcats by scoring their first two baskets after Baylor forward Cory Jefferson and Austin both made shots in the paint.
Rodriguez sank a 3, giving the Wildcats a 7-4 lead. After Jefferson again scored down low, Southwell drained his first 3, giving Kansas State a 10-6 lead four minutes into the game.
The Bears went on an 8-2 spurt powered by their big men. Jefferson, Austin and Gathers each took trips to the free throw line, where they went a combined 4-for-5, and then Gathers threw down a dunk. After Jackson scored his first points of the game, Baylor led 16-12 with 10:20 to go in the first half.
Kansas State responded with a 15-3 run that began with three straight 3s. Rodriguez played an integral part in the scoring frenzy by swishing a 3, assisting on back-to-back 3s by Southwell and then converting a basket in the paint to give the Wildcats a 23-16 advantage with 6:33 remaining until halftime.
The deficit narrowed when Baylor's guards got involved. Heslip scored his first basket of the game, and after buckets by Spradling and Southwell, both Jackson and Walton scored, pulling the Bears to 27-24 with 3:41 left in the half.
Again, just when Baylor began to close the gap, the Kansas State offense hit its stride. A 3 by Spradling began a 10-0 run that also included free throws by McGruder, another 3 by Spradling and another layup by Rodriguez.
Walton scored the last two buckets of the first half for Baylor, which went to the locker room down 38-29.