Forward Jill Witmer shoots during the Terps’ 3-2 loss to Old Dominion on Oct. 20, 2013.

Jill Witmer grimaced in pain as she sat on the turf of Boston College’s Field Hockey Complex during Sunday’s ACC championship.

With about two minutes left in the game, the Terrapins field hockey forward dove to knock away a pass intended for North Carolina midfielder Rachel Magerman inside the Terps’ circle, and both of her legs cramped after the play.

“Anything I could to keep it out of the circle,” Witmer said. “I did not want them to score.”

The No. 1 Terps were holding onto a two-goal lead with less than two minutes left, and after a quick stretch, Witmer was back on her feet and ready to support the team’s defense. Though the team’s fluid passing and strong offense has guided it to victory most of this season, the Terps’ defensive effort was key in sealing their 10th ACC championship in program history with a 2-0 victory.

The Tar Heels generated few scoring opportunities during the first 20 minutes of the second half, so they replaced goalkeeper Sassi Ammer with an extra field player with 13 minutes left in the period. The field player advantage led to more pressure from No. 3 North Carolina, but the Terps’ attackers, like Witmer, receded into a more defensive role to help the team hold off the Tar Heels’ offense.

The Terps’ frontline used its speed to slow down North Carolina’s ball movement and block crosses and shots.

“Just unbelievable,” coach Missy Meharg said. “I’m just so proud of them. So honored.”

Every member of the Terps played an important role in their defensive structure. The team’s attackers reacted quickly when they lost possession, running back to stop counterattacking chances.

The Terps also knew they had to slow down North Carolina’s star players to maintain their lead. In the Tar Heels’ ACC semifinal matchup against Syracuse, the Terps noticed most of North Carolina’s play stemmed from All-ACC midfielders Emily Wold, Nina Notman and forward Charlotte Craddock.

In addition to stopping North Carolina’s talented trio, the Terps wanted to make sure they countered with a balanced attack of their own.

“Three or four players predominantly played the ball with North Carolina,” Meharg said. “In that regard, we knew that we needed to play with all 10 and not just four, and that way we can have a real advantage.”

North Carolina had an early chance to take the lead, however, as they pressured at the start of the game and drew a penalty corner within the first three minutes. The Terps blocked Notman’s shot on the set play, though, and the Tar Heels didn’t have any more clear chances for the rest of the half.

The next time North Carolina had quality opportunities to score was in the final 10 minutes of the game. But the Terps’ emphasis on defense during the closing moments of the game prevented the Tar Heels from cutting into their lead. The Terps’ sharp attack has led to much of their success throughout the year, but in what was arguably their most important win of the season so far, defense made the difference.

“Our first and foremost thing is we want to play as a team, and that’s exactly what we did,” Witmer said. “Just giving it our all — 100 percent — and we definitely did that.”