Singleton and Allen have combined for 100 yards twice in the last six games.
The Nittany Lions converted on three fourth downs on the last drive of the game.
The Nittany Lions had nine tackles for loss and two turnovers.
A gutsy final drive won a game that came down to the wire.
Elliot Washington II and Kaden Saunders are listed as out.
The game will be broadcast on CBS for the second straight week.