Senior guard Kevin Lisch scored a team-high 13 points on six-of-11 shooting and added three assists and three rebounds in 34 minutes.
Senior guard Tommie Liddell III had six points, four assists and two rebounds in 32 minutes. Senior forward Barry Eberhardt, the last of SLU's seniors, had three points, four rebounds and two assists in 25 minutes.
Freshman forward Willie Reed had 10 points, four rebounds and two blocked shots. Freshman center Brett Thompson had five points, three blocked shots and two rebounds. Freshman point guard Kwamain Mitchell had seven points on three-of-11 shooting and had five turnovers with no assists.
Xavier led 35-25 at halftime after Saint Louis had cut a double-digit deficit to three points. The Musketeers scored the final seven points of the first half.
SLU shot 52.6 percent in the first half (10 of 19) and then 39.1 percent (nine of 23) in the second half.
Xavier led by as many as 21 points in the second half as the top seed pulled away from the Billikens.
Xavier outrebounded Saint Louis 34-21 and held a 13-3 edge in offensive rebounds.