LOWELL - The Matignon softball team officially atoned for its 0-4 start to the season Sunday with a 3-1 win over four-time defending sectional champ St. Mary’s in the Division 3 North championship at Martin Field.

Lauren Doneski threw a four-hitter to pick up the win. The senior righthander helped her cause in the third inning, lining a two-out RBI double down the left-field line to put the Warriors (17-8) on top for good.

“This season’s been awesome,’’ said Matignon coach Jessica DePolito.

“I think the talent was always there, they just had to really believe in themselves. Other teams, with the start that we had, probably would have packed it in, but we just worked harder every day and that’s why we won today.’’

Doneski, who walked two, managed to keep the Spartans (17-7) at bay without recording a strikeout.

“She did a great job mixing up her pitches and keeping their batters off balance,’’ said DePolito. “We knew going in that if we were solid defensively that we would eventually get the runs that we needed to win and that’s what happened.’’

The Spartans took a 1-0 lead in the bottom of the second inning, but the Warriors responded in the next frame with two runs.

Julia Graf led off with a walk and came around to score on a fly ball by Sarah Gauthier that was mishandled by the Spartans’ right fielder. After a sacrifice by Kayla McKinnon, Gauthier scored on Doneski’s double to put the Warriors ahead, 2-1.

Matignon continued its clutch hitting in the sixth when junior captain Ryen Cahill doubled in Doneski, who had walked to lead off the inning.

Doneski, who faced just one batter over the minimum from the third inning on, retired the Spartans in order in the seventh to seal the win.

“We started out tough, but we just kept trying and practicing hard and we turned it around,’’ said Doneski. “As seniors, we didn’t want to go out without going as far as we could in the state tournament.’’

Matignon will play Case in the EMass final.