"It was unbelievable and an absolute dream come true."
Warren now holds the single-game school record for most receptions by an offensive player, passing DaeSean Hamilton who had 14 receptions in a game in 2014.
The Nittany Lions mounted a comeback bid in the third period but fell short.
Ryan Barker's walk-off overtime field goal completed Penn State's comeback.
The Nittany Lions secured their first series sweep of the season against Union.
Singleton is Penn State's leading rusher with 53 carries, 408 yards, and three touchdowns.