UMBC senior guard Jairus Lyles (Silver Spring, Md./DeMatha) led the Retrievers with 17 points.
Trailing 36-29 at the half, Lyles scored the second half's first field goal, but UNH proceeded to outscore the Retrievers, 14-6, to take their largest lead of the game at 50-37 with 14:50 remaining.
After an exchange of baskets, UMBC turned up the pressure on the Wildcats and forced five turnovers in the next seven times UNH had the ball and ran off 12 consecutive points to slice the deficit to 52-51 after junior guard Rodney Elliott (Baltimore, Md./John Carroll) finished a lay-up on a fast break.
But UNH's Jaleen Smith converted his first of two critical and-ones, starting a 7-0 response to extend the lead back to eight.
On two occasions, the Retrievers would fight back to trim the deficit to four, On the second occasion, Lyles converted an and-one to slice the gap to 66-62 with 1:18 remaining. But, again it was Smith that was able to drive to the basket, get the bucket and the foul and extended the lead to 69-62 with 59 seconds remaining and seal the victory.
Retriever freshman and All-Rookie Team member Arkel Lamar (Bridgeport, Conn.) and sophomore Sam Schwietz (Frisco, Texas) sparked the second-half rally. Lamar scored nine points and added a game-high four steals, while Schwietz hit all three field goals (6 points) and led UMBC with eight rebounds.
Elliott was the only other Retriever in double figures with 10 points.
Smith and UNH junior post Tanner Leissner each scored 20 points to lead all players.
One of the most prolific 3-point shooting teams in the nation, UMBC only managed to convert a season-low 3 treys in 16 attempts. The Retrievers shot 43.8 percent overall and only made seven trips to the free throw line, converting six.
New Hampshire countered with 55.1 percent shooting from the floor (27-of-49) and 47.4 percent (9-of-19) from behind the arc.
UMBC never led in the first half, as UNH buried five of their first eight shots from behind the arc and creating nine Wildcat turnovers and outscored the hosts, 9-3, off miscues. Lyles was the lone Retriever to put up good first half scoring numbers, hitting 4-of-8 shots from the floor and leading the visitors with 10 points.
UMBC had the last possession of the half, but could not get a shot off and went to the intermission trailing, 36-29.
For the game, the Retrievers forced 18 turnovers and outscored UNH, 20-5, on those miscues. UNH won the board battle, 37-25, but UMBC outscored the Wildcats in the paint, 42-24.
Despite the setback, UMBC reached the 18-win plateau for just the fourth time in 30 NCAA Division I seasons and remains one of the nation's most improved teams from a year ago.