MANSFIELD, Conn. – Critical mistakes and a sputtering offense proved insurmountable Thursday night as St. Joseph’s College strived to stay in the NCAA Division III New England Regionals winners’ bracket.

Ed Donovan pitched a four-hitter and third-seeded Trinity took advantage of three mistakes in posting a 4-0 baseball victory.

The second-seeded Monks (38-6) slipped into the losers’ bracket for a game with Keene (N.H.) State at 1:15 p.m. today. If they survive, they’ll play against the Bowdoin-Western New England winner about 7:45.

Donovan (6-2) threw just 98 pitches, struck out four, didn’t walk a batter and only got into one three-ball count — against St. Joseph’s leadoff hitter Nate Martin.

Trinity (34-9), which meets Wheaton College in a game between the tournament’s remaining unbeaten teams, jumped on St. Joseph’s starter Joe Gruntkosky (3-2) for two runs in the first inning.

Michael Rueger drilled a one-out single and advanced on a walk to Kevin Mortimer. Joe Papa (4 for 5) lined a single, scoring Rueger and sending Mortimer to third. Adam Moossmann added a two-out RBI single.

Trinity tacked on an unearned run in the fourth.

After a leadoff single by Bryan Wolfe, Kyle Decker laid down a bunt that catcher Joe Coyne threw wide of second for an error. A sacrifice fly by Alex Almeida scored Wolfe.

The Monks, held to one single through four innings, had their bid to get back in the game erased by a baserunning mistake in the fifth.

Nic Lops began the inning with a shot toward the right-field corner and pulled safely into second. But Trinity appealed that he missed the first-base bag, umpire Jeff Mertzel confirmed it, and the Monks went out in order.

Gruntkosky yielded eight hits and three walks in 51/3 innings but Trinity stranded nine through six innings. The trend continued as the Bantams left two on in the seventh and eighth against reliever Alex Valenti. Trinity stranded 15 in all.

Brandon Chase had an infield hit for the Monks leading off the sixth but never reached second. In the seventh, Mike Pratt led off with a single, Alex Lorenc was hit by a pitch and both moved into scoring position on a fielder’s-choice grounder by Dan Brown, but Sam Butts was nipped at first on a chopper to third.

Trinity added another unearned run in the ninth when Valenti’s error led to a two-out RBI single by Decker.

The Monks, who came into the tournament batting .335, have just nine singles in 57 at-bats (.158) in splitting two games. The shutout was St. Joseph’s first in 62 games dating back to April 16, 2011.