WPI (20-2, 10-1), ranked 24th in the nation, could have clinched the NEWMAC regular season championship with a win.
Coast Guard (12-9, 4-6), which has won four of its last five, had its biggest lead at 34-25 in the closing seconds of the first half before Brian Stelle hit a three-pointer at the buzzer to pull WPI to within 34-28 at halftime.
Coast Guard built a 10 point lead at 43-33 with 14:40 left and WPI could only get as close as eight points on two different occasions.
Craig Johnson was five-for-five from the floor and he and Al Sowers each finished with 12 points for Coast Guard.
Steele led WPI with 19 points while Mike Prestileo added 16 points. Ryan Cain, the leading scorer in the NEWMAC was held to 10 points, just one in the first half.