Justin Koslowski scored 20 points and Dan Graf scored 18 points for the Auggies, who halted a nine-game losing streak to St. Thomas and handed the Tommies their first conference loss.
Augsburg, which is 0-4 at home this season, won its second conference road game under first-year head coach Aaron Griess.
UST remained atop the conference standings by one-half game over St. Mary's and idle St. John's, who are both 3-1 in the conference. Concordia and Gustavus both lost on the road Monday to take their second MIAC defeats.
Rosefelt, who scored 18 first-half points, made his first 11 shots and finished 16-of-19 from the field. UST junior guard Bryan Schnettler added nine points and six rebounds but made just 1-of-9 from 3-point range after sinking 12 treys in two victories last week.
The Tommies outrebounded Augsburg 41-28 but made just 3-of-19 from 3-point range to the Auggies' 7-of-16. After rallying from a 12-point deficit, the Toms were outscored 10-3 in a late 6:00 stretch.
UST nearly forced overtime after trailing 61-53 with 34 seconds to play. Augsburg had a turnover and made just 1-of-4 free throws during a 6-1 UST run. Trailing 61-59, the Toms missed a tying shot with :07 to go. After the Auggies made one of two free throws with 4.5 seconds remaining, Sean Sweeney's potential tying 3-point shot at the buzzer danced on the rim and fell off.
Koslowski scored 15 points early as the Auggies raced to a 24-14 lead. The Tommies pulled within 31-29 at halftime and led 35-34 with 15:24 to play. But three 3-point baskets fueled a 14-1 Auggie run that put the visitors in front 48-36 with 9:55 to go.
Sweeney's 3-pointer capped a 13-1 Tommie run that pulled St. Thomas to within 50-49 with 6:34 to go. But UST missed its next seven shots and trailed by eight in the closing minute before its comeback fell short.
St. Thomas is home to face St. John's Wednesday (7:30 p.m.) while Augsburg is off until Saturday when it hosts Hamline.