Defender Brian Cooper checks a Duke player during the No. 2 Terps’ 10-6 win over the No. 1 Blue Devils on March 1, 2014.

The Terrapins men’s lacrosse team led Stony Brook by two goals with just more than eight minutes remaining in regulation Saturday when midfielder Mike Andreassi tried to dodge Terps defensive midfielder Brian Cooper in front of the cage.

The Seawolves had scored four unanswered goals during the opening seven minutes of the fourth quarter, threatening to complete an improbable comeback against the No. 1 Terps at Kenneth P. LaValle Stadium in Stony Brook, N.Y.

But Cooper knocked the ball loose from Andreassi’s stick, picked up the ground ball and started a fast break the other way. After crossing midfield, he dished to midfielder Henry West, who eventually found midfielder Bryan Cole for his second goal of the contest, ending the Seawolves’ scoring run.

Midfielder Mike Chanenchuk added a goal two minutes later, and the Terps escaped with an 11-8 victory to remain undefeated. But Cooper’s forced turnover prevented a collapse on the road. It was the kind of game-changing play coaches and players in the program have come to expect from the senior.

“We just know every time he’s on the field, he’s going to impact our team for the better,” goalkeeper Niko Amato said. “He demands a lot out of himself, and he demands a lot out of the rest of our teammates.”

After spending his freshman season as a short-stick defensive midfielder, Cooper made the transition to defenseman as a sophomore. Cooper said he was likely going to be third on the depth chart for defensive midfielers that year, and the position switch would provide him with more playing time.

He started all 18 games on defense in 2012, collecting 36 ground balls while forcing 20 turnovers. The following season, he began preseason practices in the fall with a long pole. But the return of defensemen Casey Ikeda from injury and the addition of then-freshman defensemen Matt Dunn meant Cooper would again be challenged for his spot. Not to mention, beyond midfielder Landon Carr, the Terps lacked depth at defensive midfield.

So after several recommendations from coaches, Cooper once again returned to his natural position with a short stick, collecting 10 ground balls and forcing 10 turnovers in 11 games.

Entering this season, though, there were fewer questions regarding Cooper’s playing time. He is now the leader of the defensive midfield and a consistent presence for coach John Tillman’s No. 3 defense in the nation.

“There are a lot of cool things about it,” said Cooper, who has collected 14 ground balls, forced five turnovers and notched one assist so far this year. “You just get dodged more. You get to play the wings on faceoffs. You get ground balls and push it offensively. It’s just a fun position to play.”

Aside from games, Tillman said Cooper also makes massive contributions in practice. He never takes a day off, and he brings a unique intensity to the training field, providing a culture of competition that has helped the program’s younger players flourish in the first five games this year.

“He’s the kind of guy that if he’s not practicing, you just know he’s not there,” Tillman said. “The energy that he brings, just the leadership, the toughness, the heart — he’s a guy that’s critical for us.”

Cooper said he has modeled his practice style after those of older players, including his brother Kevin, who was on the team when Cooper arrived in College Park as a freshman in 2010.

“I remember those guys as seniors just coming out every day, and they just brought energy,” Cooper said. “And when a senior leader does that, it kind of spreads throughout the team.”

Growing up in Crofton, Cooper always envisioned playing as a Terp at Byrd Stadium.

And whenever he doesn’t feel 100 percent and thinks he can’t bring his characteristic passion to practice that day, he remembers back to his days as a kid when playing college lacrosse was just a dream.

That’s often the motivation he needs to stay on the practice field and make plays like the one that staved off Stony Brook’s late comeback.

“You kind of take it for granted sometimes,” Cooper said. “But it’s a really cool thing to put on the Maryland jersey every day.”