Mercer, the Atlantic Sun regular-season champion, improved to 2-1 this season against Southeastern Conference foes. Mercer lost 58-49 at Georgia on Dec. 18 and won 66-59 at Alabama on Dec. 22.
The Bears (24-11) will play at Brigham Young in the second round.
Trae Golden scored 20 points for Tennessee (20-13) before only 4,468 fans at the 21,678-seat Thompson-Boling Arena.
IOWA 68, INDIANA STATE 52
In Iowa City, Iowa, Devyn Marble scored 24 points, Aaron White added 11 with 13 rebounds and Iowa (22-12) cruised past Indiana State (18-15) in the opening round.
The Hawkeyes will play host Stony Brook in the second round on Friday night.
STONY BROOK 71, MASSACHUSETTS 58
In Amherst, Mass., Anthony Jackson and Dave Coley scored 20 points each and Stony Brook (25-7) beat Massachusetts (25-7) in the first round.
PROVIDENCE 75, CHARLOTTE 66
In Providence, R.I., Vincent Council, the only senior on the roster, scored eight consecutive points to key a second-half charge that led Providence (18-14) over Charlotte (21-12) in the opening round.
Providence will play host to Robert Morris, which upset defending national champion Kentucky the previous night, either Sunday or Monday.