The win was the fifth straight for Illinois (20-8, 7-7 Big Ten). But facing a team that hadn't won since late December, it didn't come easy.
Jermaine Marshall's 3-pointer brought Penn State within 62-59 with 5 seconds left. Richardson then sank a pair of free throws that sealed the win.
Illinois led 29-20 at the end of a brutal first half.
The Illini's Brandon Paul entered the game a point shy of 1,500 in his career. It took him almost 17 minutes to get it. He finished with 16.
Penn State (8-18, 0-14) has lost 14 straight. The Nittany Lions committed 31 fouls and sent the Illini to the line 36 times. They made 23.
Jermaine Marshall led Penn State with 20 points.