Dez Wells converted an offensive rebound into a three-point play with 1:44 left and Varun Ram stripped away
The fourth-seeded Terrapins (28-6), in the tournament for the first time since 2010, advanced to face West Virginia in a Midwest Regional game on Sunday.
Alec Peters led 13th-seeded Valparaiso (28-6) with 18 points.
The Crusaders were down 3 with one last chance for coach Bryce Drew to draw up a winning play. He didn't need a length of the court pass as he did when he made the most famous shot in school history back in the 1998 tournament, but Valparaiso did need a three.
Keith Carter went up for one in the corner, but Ram reached in and swiped the ball away — maybe getting some of Carter's arm in the process.
Wells finished with 14 points for the Terps, including that three-point play that made it 65-61. Melo Trimble had 14 points and 10 rebounds for Maryland, playing in its first NCAA Tournament under fourth-year Coach
The Terrapins were expected to be middle of the pack in their first season in the Big Ten, but instead finished second behind
E. Victor Nickerson dropped in a three-pointer with 6:37 left to tie the game at 49 for Valpo and make Maryland call a timeout.
The Terps got the lead back with a couple of free throws, and then Trimble snagged a Valpo pass in the paint, broke quickly the other way and found Damonte Dodd for a layup to put the Terps up 53-49 with 6:00 left.
But the Terps could never put away the Crusaders, who shot 12 for 27 from three-point range.
Tevonn Walker, who scored 14 points, made one free throw with 1:00 left to make it 65-62, but Valpo couldn't get its first NCAA Tournament win since Drew's buzz-beater against Mississippi sparked a surprising Sweet Sixteen run 17 years ago.
Jared Nickens made four three-pointers in the first half to help Maryland to a 31-27 lead at the break. Three-point shooting and offensive rebounds kept Valpo close.