At its simplest, high school girls lacrosse is an 11-on-11 contest, plus goalkeepers, that turns into a 7-on-7 inside the restraining line. Inside those final 30 yards is where the scoring occurs as seven defenders and midfielders try to work to frustrate the opposing seven offensive players.

But when you have a goalkeeper as talented and athletic as Abigail Dieumegard, that goalie can appear more like an eighth defender. That can be devastating to an opposing offense.

Dieumegard’s dominance was on display again on Tuesday for Islip in an 8-5 home victory over Mount Sinai in Suffolk Division II girls lacrosse play. Dieumegard had 10 saves, a caused turnover and two ground balls to anchor the defense.

“We put all of our confidence in Abby,” coach Taryn Ohlmiller said. “She is our brick wall and we rely on her a lot. She’s like the eighth defender on the field and that’s what’s really cool. She’s probably one of our most athletic players and the fact that she’s able to play that eighth defensive position, it really leads to a lot of stops for us.”

Dieumegard played a key role in Islip taking a 4-1 lead after the first quarter and a 6-2 advantage at halftime. Islip (8-6, 6-6) led by at least three goals the remainder of the contest.

Teagan Rao led the offense with three goals and an assist, including a goal with 19.7 seconds left in the second quarter and another goal as time expired in the third quarter for well-timed late scores.

“We slowed the ball down and it was big to get those last-second goals to help us win at the end of the day,” Rao said. … “It’s really exciting because I feel this win will help us get into the playoffs and hopefully have a big run.”

Tessa Smith had two goals, Caitlin Barnes added a goal and an assist and Reese Wallace had three caused turnovers and a goal in the win. Sophia Masone had two goals and Alexa Spallina had a goal and two assists for Mt. Sinai (7-6, 6-6).

Although Dieumegard made multiple athletic saves and plays, the junior passed the credit to those in front of her.

“My defense helped me a lot and they kept me in the game and kept the positive energy,” Dieumegard said. “I feel everyone just wanted it and that energy just spread all over.”

But Dieumegard’s importance to the team can’t be overstated and her play was pivotal to Tuesday’s victory.

“Every time she makes a save, the sideline is going crazy and the defense feels just a little bit more confident,” Ohlmiller said. “And I feel little by little, every time she makes a save for us, it just trickles to the rest of the team, which is awesome.”