GROTON — For those attending Groton-Dunstable softball games this season, not a lot of time will have to be set aside. With senior Jess O’Sullivan on the mound, the games will proceed at a lively pace and runs will be at a premium.

O’Sullivan turned in another masterpiece as the Lady Crusaders slipped past MidWach B rival Quabbin 1-0. The flame-throwing left-hander allowed only two hits and a walk, while notching 19 strikeouts as the Lady Crusaders improved to 5-1 for the season.

O’Sullivan needed to be at her best as Quabbin pitcher Maggie Lacwason proved to be hard to solve for the Groton-Dunstable offense. Lacwason allowed only four hits while striking out five and walking none and suffered a tough defeat when the Lady Crusaders pushed across an unearned run in the bottom of the sixth.

The game was scoreless heading to the bottom of the sixth when Ali Kessler led off with a double. Kiersten Bieren advanced her to third with a perfect sacrifice bunt, setting the stage for the game’s decisive play. Meg McLean hit a slow roller down the third base line and hustled to first for a hit. Quabbin third baseman Jackie Welch made a heads-up play, faking a throw to first and Kessler became trapped in a rundown between third and home. It ended on a happy note for the Lady Crusaders when the throw to the plate was wide and Kessler scored the only run of the game.

With that run under her belt, O’Sullivan smelled the finish line and struck out the side in the top of of the seventh to seal the deal.

“It was a tough play for Ali,” said Groton-Dunstable coach Derek Asadoorian. “If the throw goes to first she is going to break for the plate, but she needs to get as far down the line as possible. It ended up working out.

“We are going to be aggressive this season,” said Asadoorian. “Jess kept us in the game and was outstanding. Ali is doing a good job for us and we found a way to get her home. We hit the ball hard on occasions, but Quabbin came up with some good defensive plays.”

Quabbin lead-off hitter Theresa Tremblay led off the game by drawing a walk and stole second, but O’Sullivan bore down and struck out the next three hitters to escape. Quabbin mounted threats in both the second and third innings when Brittany Peterson and Lindsay Howland singled and advanced to second base, but O’Sullivan had her strikeout pitch working. The first 15 Quabbin outs in the contest were strikeouts.

Groton-Dunstable threatened in the bottom of the first when McLean reached on a bunt single and stole second, but the inning ended when Quabbin leftfielder Kelsey Carpenter caught a fly ball and fired to second base to complete a double play.

Lacwason breezed through the next three innings, facing only nine batters before the Lady Crusaders mounted another threat in the bottom of the fifth. Kate Stowell blasted a long double to left field that just missed going out, and one out later moved to third on a sacrifice bunt by Kylie Blodgett, but Lacwason induced an inning-ending groundout to keep the game scoreless.

Quabbin made some contact in the top of the sixth, with a pop-out and flyout, but O’Sullivan retired the side in order, setting the stage for the decisive run in the bottom of the inning.

McLean was the only player in the game with more than one hit as she singled twice.