The University of Maryland women's lacrosse team, entering the NCAA championships confident of victory, was brought back to reality today by a team it had beaten handily in the regular season.

New Hampshire, with a tough zone defense and superior team speed, pulled its second upset in two weeks, this time defeating the second-seeded Terrapins, 6-5, for the NCAA title at the University of Pennsylvania's Franklin Field.

The Wildcats (11-3), who had beaten defending champion Temple last Sunday, won on a goal by Ann G. Sherer past freshman goalie Kim Chrosiewski, who had entered the game just 10 minutes earlier. Chrosiewski relieved senior Mary Bernard 9:36 into the second half with the score 5-4, but gave up goals by Sarah Kittredge and Sherer. She was not credited with any saves.

The major Maryland problem was in penetrating the New Hampshire zone, a defense that has given the Terrapins trouble in past seasons. "We had to play a strong defense," said New Hampshire Coach Martha Marisa Didio. "It is a key against a team that technically, one-on-one, may have a little better skills."

Maryland (15-2) took a 2-0 lead in the first half on goals by Wendy Beer and Kay Ruffino. Pauline Collins of New Hampshire then brought the Wildcats within 2-1, beating Bernard at 7:12 of the first half. After Anysia Fedec gave Maryland a 3-1 lead, Collins scored another and Suzie Haynes scored with 40 seconds left in the half to tie the score at 3. All-America Karen Trudel scored following an assist from Fedec at 4:15 of the second half to give Maryland the lead again, 4-3, but the Wildcats came back 46 seconds later on a goal by Barb Marois.

"It is a frustrating loss. New Hampshire played an outstanding game," said Maryland Coach Sue Tyler. "Today they took us out of our game plan . . . They ran the ball more than we are accustomed to."

Goalie Robin Balducci had 14 saves for New Hampshire.

Maryland, which lost to Temple in the 1984 title game, beat New Hampshire, 14-9, earlier this season.