Twice Dayton had 14-point leads, up 21-7 before the Sycamores drove 95 yards in the final minute of the first half, cutting it to 21-14, and tying the game at 21 early in the third quarter.
The Flyers responded with two TD runs by quarterback Jack Cook to give Dayton a 35-21 lead at the end of three quarters.
However, Indiana State scored on the first play of the fourth quarter and after Dayton went three and out, the Sycamores tied the game on a 5-yard run by Chris Childers with 10:53 to play.
The two teams exchanged possessions and the Flyers took over on their own 15 yard line with 6:32 to play.
Ten plays later Prophit found the end zone. Indiana State drove to the Flyers 26 yard line, before Rumpke’s interception with 9 seconds to play. Rumpke was playing his first collegiate game filling in for captain Andrew Lutgens, who was injured in the first quarter.
“He was right where he was supposed to be on that play,” said UD coach Rick Chamberlin said.
Jack Cook was 21-29 passing for 251 yards and two touchdowns, including 132 yards of that to pre-season All-American tight end Adam Trautmann who had a career-high 11 catches.
“This is the greatest win I have ever been a part of,” said Trautman. “Jack knows where I like the ball, and he just puts it there.”
Chamberlin put the victory in perspective: “This is at the top of all the games I’ve been in as a player and a coach. As good as they are. As highly ranked. No one thought we could do this.”
Dayton at Robert Morris, 3 p.m., 1290, 95.7 WHIO Radio