The Tommies (5-1 overall, 4-0 MIAC), who won their fifth game in a row, shot 65% from the field (35-of-54). UST posted a 37-20 rebounding advantage as it rolled to a surprising margin over Gustavus (5-1, 2-1), the defending conference champions, before a crowd of more than 1,400.
The Toms used a 28-6 run over the last 12:00 of the first half to build a 46-18 halftime lead. The Gusties never got closer than 27 in the second half.
The Gusties, who shot an amazing 58% from the field in their opening five victories, shot just 33% from the field Wednesday in suffering one of their most one-sided home losses in memory.
Phil Sowden had 12 points and Andrew Olson had 10 for the Gusties.
Gustavus had won 25 of its last 26 MIAC home games -- including two 10-point wins over St. Thomas last season -- and was 56-7 vs. conference foes at home since February 2000.
The 6-foot-8 Rosefelt made 12-of-15 shots from the field as he scored in double figures for the 26th time in 32 games at St. Thomas.
UST junior guard Bryan Schnettler made 5-of-8 from 3-point range and scored 21 points. Senior forward Joey Shimek scored 10 and senior guard Sean Sweeney had nine points and five assists. The unranked Tommies have a one-game lead over St. John's (3-1) and a 1.5-game lead over Concordia and Gustavus (both 2-1) early in the 20-game conference race.
On his post-game radio show, Gustavus men's coach Mark Hanson praised the Tommies. "They were outstanding. They were completely at the top of their game -- at least I hope they were at the top of their game. They were definitely ready for us. I didn't think we weren't ready, but I don't know we were ready for that kind of performance from them."
The Toms are off the next 14 days and play at UW-LaCrosse Dec. 21, then play Dec. 29-20 in the UW-River Falls tourney. They resume conference play Jan. 2 at home vs. Augsburg.
Gustavus plays Friday at Minnesota-Morris.