Danny Thompson had 14 points and seven rebounds and Kelvin Parker added 13 points for the Mountaineers (1-3), who trailed by 33 points at halftime.
Minnesota shot 50 percent and committed just nine turnovers. It turned into a rout early when the Gophers opened the game on a 25-4 run.
Williams didn't play in the second half, doing all the damage he needed to do in the first 20 minutes.
The game was all but over after the first three minutes. Williams had two dunks and Austin Hollins hit two 3-pointers — turning one of them into a four-point play — during an 11-0 run to start the game, and the Gophers were off and running.
Gophers coach Tubby Smith has been urging the super-athletic Williams to be more assertive around the basket, and he finally started doing that against the totally overmatched Mountaineers front court. Two of his dunks came on monstrous putbacks of missed shots by teammates.
The Gophers led 25-4 at the midway point of the first half and did most of their damage without the help of star forward Trevor Mbakwe, who had been a one-man team in Minnesota's underwhelming first three games of the season. The burly forward carried the team's struggling offense in wins over Bucknell, South Dakota State and Fairfield, but he was able to get the night off on Monday.
Mbakwe entered the game averaging 18 points and 10 rebounds, but had just two points and five boards in the first half as the Gophers built their huge lead. He finished with 10 points and nine rebounds and seemed perfectly content letting his teammates do the heavy lifting for once. He could afford to do that against the small school from Emmitsburg, Md.
The Mountaineers turned the ball over 21 times, including 10 by Josh Castellanos, and didn't have anyone close to athletic enough to keep Williams below the rim.
Thompson was the only Mountaineer to score in the first 16 minutes of the game. He tallied Mount St. Mary's first 10 points and didn't receive any help until Kristjan Krajina, who missed the first three games because of a suspension, scored on a putback with 4:09 to go in the first half to make the score 39-12.
Sampson sat out the game purely for precautionary reasons, resting up as the Gophers prepare to see their nonconference schedule get a little tougher. They are scheduled to leave for Orlando, Fla., on Tuesday to play in the Old Spice Classic, a tournament that also features DePaul, Texas Tech and Indiana State.