Curtis Kelly and Jacob Pullen added 15 points each for the Wildcats, who also extended their winning streak over the Cyclones to eight games dating to 2006.
Kansas State (19-4, 6-3) opened the second half with a 17-4 run, turning a six-point deficit into a 48-39 lead in less than 5 minutes. Iowa State got as close as 60-56 before an 8-0 run by the Wildcats secured the victory.
Craig Brackins had 29 points and 12 rebounds for Iowa State (13-10, 2-6), which lost for the fifth time in six games. The Cyclones have dropped 19 straight against ranked opponents.
Iowa State threw a bit of a late scare into the Wildcats, though, hitting four 3s in the final 1:01 to crawl back within 79-75. The Cyclones then got the ball back with under 10 seconds left, but two 3-point attempts missed the mark and time ran out on what little chance they had for a comeback.
Iowa State fell behind by as much as 11 points before pulling within four with 5:50 left. But freshman Rodney McGruder found Kelly for a jumper off a turnover by Brackins, and Clemente's 3 put Kansas State back ahead 68-56 with 4:33 left.
Clemente, who was 6 of 8 from 3-point range, has hit 11 3s in his last two games.
Kansas State turned to its specialty - creating easy baskets off turnovers - to grab a comfortable lead early in the second half.
Clemente keyed the spurt with two pull-up 3s from the top of the key, giving Kansas State a 41-39 lead. Jamar Samuels and Wally Judge then converted steals into transition dunks, pushing the lead to nine with 15:04 left.
The Wildcats scored 12 points off turnovers in the first 8 minutes of the second half - after getting just one bucket off Iowa State miscues in the first half.
After opening Big 12 play with a road loss at Missouri, the Wildcats have now beaten Colorado, No. 20 Baylor, Nebraska and Iowa State in succession on the road. With home games against cellar dwellers Colorado and Nebraska on the docket next week, Kansas State has put itself in position to build some momentum heading into the home stretch of the regular season.
Brackins scored 14 points in the first half and freshman Chris Colvin's late 3 from the wing - the only one Iowa State hit in nine tries before halftime - helped give the Cyclones a 35-31 halftime lead.
But once again, Iowa State couldn't keep up. The Cyclones, who are down to just eight available scholarship players, trailed by four at halftime at No. 20 Baylor on Wednesday before falling 84-63.
Marquis Gilstrap had 18 points for Iowa State, which fell to 1-5 since junior guard Lucca Staiger's stunning departure to play professionally in his native Germany.
Iowa State wore pink-and-white uniforms and bright pink sneakers to promote breast cancer awareness. Its students also got into the act, filling both sections behind the baskets in bright pink T-shirts reading "One Cause."
It's an issue that hits close to home for the Cyclones. Coach Greg McDermott's wife, Theresa, and graduate assistant coach Bryan Petersen's mother, Karen, are both breast cancer survivors.