Justin Goldsborough's layup with 17:01 left broke a 34-all tie, giving the Mountain Hawks (9-9, 3-4 Patriot League) the lead for good and sparking a 10-0 run over the next 3:16.
The Midshipmen (7-12, 3-4) closed the gap to 46-40 on Will Kelly's layup at 7:32, but Lehigh stretched its lead with another run to 57-42 on Kahron Ross' free throw with 2:59 left.
Tim Kempton added 10 points and nine boards for Lehigh. Goldsborough also scored 10 and Ross had nine points and seven assists.
The Mids trailed only 29-28 at the break and opened the scoring in the second half for their last lead at 30-29.