Trailing 36-34 with 24 seconds left, Robinson hit a layup to tie the score and send the game into overtime. The Mountaineers (5-10, 2-0 Northeast Conference) opened the extra period on a 6-0 run, highlighted by a Charles Glover 3-pointer.
A Tyreek Jewell layup clawed St. Francis back to 42-38, but Robinson drilled two at the free throw line to put the game away.
BK Ashe finished with 10 points and nine rebounds for Mount St. Mary's.
Jewell scored 13 points and added eight rebounds to lead St. Francis (4-11, 0-2). Yunus Hopkinson had 11 points for the Terriers.
Neither team reached the 30 percent plateau in shooting percentage, and they combined for just 31 total field goals.