Nolan Bieck kicked his third field goal, a 42-yarder, to give Princeton (5-3, 2-3 Ivy League) a 23-20 lead in overtime. Two plays later, Fiore's score ended it.
Torgersen completed 21 of 27 passes for 178 yards and added a career-high 96 yards rushing on 13 carries. Justin Watson had 117 yards receiving on a career-best 13 catches for Penn (5-3, 4-1), which has won four in a row for the first time since 2012.
Tre Solomon's 4-yard scoring run gave Penn a 10-3 lead early in the second quarter, but Joe Rhattigan scored two rushing touchdowns and Bieck kicked a 39-yarder to give the Tigers a 20-10 lead at halftime.
Solomon added a 3-yard touchdown run in the third and Jimmy Gammill kicked a 42-yard field 3:22 left in regulation to tie it.