Lewis Jackson and D.J. Byrd added 13 points each and Terone Johnson scored 12 for Purdue (17-9, 7-6 Big Ten).
The Illini (16-10, 5-8) repeatedly closed to within two over the game’s final 10 minutes. But the Boilermakers found a way to climb away every time.
The last came on Hummel’s free throw with 19.5 seconds to play that put the Boilers up 65-62. With Illinois forced to foul, Hummel then sank two more.
Freshman Tracy Abrams led Illinois with a career-high 22 points. Brandon Paul added 19 points.
Illinois has lost seven of eight while Purdue has won two straight to stay in the top half of the Big Ten.