Lin, a three-time All-Ivy League selection, watched the Crimson move one win closer to an Ivy title from about a dozen rows behind the Harvard bench. Early in the second half, Lin stood and waved to the crowd. ''Jeremy Lin for Mayor,'' shouted one fan.
Harvard (25-4, 11-2) leads Pennsylvania by a half-game in the Ivy race.
Harvard led 34-30 at halftime, but Columbia (14-15, 3-10) tied it at 62-all on two late layups by Mark Cisco (12 points). In overtime, Casey quickly hit a jumper, fed Laurent Rivard for a 3 and hit a trey of his own for a 70-64 lead.
Oliver McNally (12 points), who missed a 3-pointer with 0:02 left in regulation, went 7 of 8 from the foul line in the last 45 seconds of overtime. Harvard hit 17 of 20 free throws, Columbia 8 of 13.
Brian Barbour led Columbia with 23 points. Harvard's Keith Wright scored 16.
- Jeremy Lin