Dre Smith hit two foul shots with 5 seconds left in regulation to give George Mason a 65-62 lead before Battle hurried down the court for his buzzer-beating 3 for Penn State (23-11). It was Battle's first bucket of the second half after missing his first seven shots.
Battle hit two more 3s in overtime, scoring all but four of Penn State's 12 points in the extra frame.
John Vaughn's deep 3 with 7.7 seconds in OT drew George Mason within 75-73, but Stanley Pringle hit two foul shots with 7.0 seconds left to finally seal the win.
Cameron Long had 16 points to lead George Mason (22-11).
RHODE ISLAND 68, NIAGARA 62
In Lewiston, N.Y., Kahiem Seawright scored 20 points in the second half -- including all 10 for Rhode Island during a critical run -- and the Rams won their first-round game.
Jimmy Baron had 20, including six free throws in the final 40 seconds, for the sixth-seeded Rams (23-10), who snapped a two-game losing streak. Seawright finished with 23 points for the Rams, who are making their 13th NIT appearance and improved to 7-6 in tournament-opening games. Rhode Island plays Penn State in the second round.
Anthony Nelson scored 14 for the poor-shooting Purple Eagles, who finished 21 of 59 from the field, and 7 of 27 in 3-point attempts. Third-seeded Niagara (26-9) had a seven-game home win streak snapped.
With Rhode Island trailing 41-34, the Rams gained momentum courtesy of Seawright, who sparked a 10-2 run by hitting a free throw after he missed the first attempt. The senior forward was then nearly perfect, scoring 10 in a row over a span of 2:42 that put the Rams ahead 43-41 with 12:20 remaining.