Five players reached double figures in scoring for the third-seeded Huskies (22-11), who will face No. 1 seed William & Mary on Monday night. The winner receives an automatic bid to the NCAA Tournament.
Jordon Talley scored 18 and Craig Ponder added 17 for second-seeded UNCW (18-13). The Seahawks twice beat Northeastern during the regular season, but in this one they fell behind with 11:40 left and never caught up.
UNCW scored the game's first six points, which ended up being the biggest lead by either team until a basket by Eatherton made it 59-53.
It was 64-59 before a three-point play by Eatherton made it an eight-point game with three minutes to go.