EXETER — It may not have been the team's best performance of the season, but Bedford High played well enough to defeat Portsmouth, 13-10, Sunday night and advance to the Division II boys' lacrosse championship game.

Senior Nathan Larrivee, senior Jared Hornsby, junior Jason Campbell and junior David Phelps each scored four goals for the top-seeded Bulldogs, who improved their record to 16-0. Bedford will meet third-seeded St. Thomas for the title Tuesday night (7) at Exeter High School.

Bedford defeated St. Thomas, 8-6, during the regular season.

“They're two totally different teams,” Portsmouth coach Peter Latchaw said. “It's gonna be an interesting matchup because Bedford has a lot of offensive guns, and St. Thomas is very much a defensive powerhouse. It's two very, very different styles.”

Bedford led Portsmouth 6-4 at halftime and 10-7 after three quarters.

“A win is a win — that's the way I look at it,” Bedford coach Matthew Guerard said. “We didn't play our best. We turned the ball over quite a bit, which is uncharacteristic for us, but we'll take it.”

Fourth-seeded Portsmouth received three goals from senior attack Charlie Duprey. The Bulldogs beat the Clippers 17-4 during the regular season.

Portsmouth made it a 6-5 game by scoring the first goal in the third quarter, but Bedford responded by scoring the next three goals. Portsmouth completed its season with an 11-5 record.

Bedford will be trying to win the program's first state championship Tuesday. The Bulldogs lost to Bow in the 2010 championship game, and to Souhegan in last year's semifinals.

“I don't expect anything from St. Thomas but their best game,” Guerard said. “We'll come with our best game Tuesday night and we'll see who wins.”

St. Thomas 6, Bow 3: St. Thomas of Dover received a goal and 10 saves from junior goaltender Sebastian Olson in its semifinal victory.

Olson's goal gave the Saints a 4-2 lead with 58.7 seconds left in the first half.

“I was expecting a good defensive game on our part, but I certainly wasn't expecting our goalie to score a goal and I wasn't sure we could hold them to three,” St. Thomas coach Barry Katz said. “Lacrosse is a game of momentum. When (Olson) scored it gave the kids a big lift heading into the locker room.”

Sophomore Jake Geppert added three goals for third-seeded St. Thomas, which raised its record to 13-3.

Second-seeded Bow played without leading scorer Devin Calkins, who suffered an ankle injury in practice Saturday. Calkins, who scored seven goals in Bow's quarterfinal-round victory over Winnacunnet, led the Falcons with 60 points this season.

“Our offense just couldn't get things going” Bow coach Ross Mondello said. “We had a big piece of our attack out for today. We were looking for somebody to lead the team, and all year we haven't been that way. We've been pretty balanced.

“I told the guys we can't have excuses. It's gonna be a team effort win or lose. I thought their goaltender played great. He got hot early and stayed hot for most of the game.”

Calkins scored five goals when Bow defeated St. Thomas, 8-7, in the final regular-season game for each team.

Junior Daniel Crisman scored two goals for the Falcons, who completed their season with a 13-3 record.

St. Thomas will be seeking the program's first state title since the Saints won the Division II championship in 2007.

The guys did a great job,” Katz said. “I'm really proud of them.”