Glass and Ben Crenca led the Catamounts (4-2) with 13 points each. It was Vermont’s second win in a row by two points. The Catamounts defeated Old Dominion 65-63 in overtime on Wednesday.
Vermont matched its biggest lead of the second half when Luke Apfeld hit a layup with 1:36 to play for a 62-54 advantage.
Siena made an 8-0 run, aided by two Vermont turnovers, to tie the game 62-62 on a layup by O.D. Anosike with 25 seconds remaining. Anosike had 24 points and 10 rebounds.
Hot shooting kept the Saints close throughout as they shot 50 percent (22 of 44) for the game and 52.4 percent (11-21) in the second half.
Kyle Downey added 15 and Evan Hymes had 10 for the Siena (2-3), which has lost three games in a row.