The Bishop Guertin girls’ basketball team pounced on Merrimack early and won the battle between the only unbeaten teams in Division I by posting a convincing 63-23 victory Friday night in Nashua.

BG, which raised its record to 13-0, led 18-6 after one quarter and 37-13 at halftime. The loss dropped Merrimack to 12-1.

Windham 43, Portsmouth 41: In Windham, the Jaguars (5-7) prevailed by overcoming a 10-point deficit at the start of the fourth quarter. Liv Tsetilas scored 16 points for Windham, which took its first lead of the game with 36 seconds to play. Sarah Dempsey added eight points in the victory, with all eight coming from the free throw line. Corrine Lamond led Portsmouth (7-6) with nine points.

Nashua South 39, Nashua North 37: In Nashua, Julianna Martin scored 16 points to lead the South (6-7) offense at North. Kirsten McIntire added 11 for the Panthers, who also received six points from Aryanna Murray. North fell to 3-10 with the loss.

Exeter 61, Winnacunnet 44: In Hampton, Kate Heslop scored a team-high 14 points for the Blue Hawks, who also received a 13-point performance from Syd Taylor. Heslop tossed in four 3-pointers. Exeter improved to 4-8 in Division I. Winnacunnet dropped to 1-12.

Dover 49, Spaulding 42: In Dover, Jenna Philbrook and Ashley Troger each scored 10 points for Spaulding, which dropped to 10-1 in Division II. Dover improved to 2-12 in Division I.

Boys’ basketball

Hopkinton 57, Campbell 54: In Litchfield, Campbell led by four points after three quarters, but Hopkinton (10-3) scored 21 points in the fourth. Hopkinton’s Kevin Newton-Delgado led all scorers with 20 points. Owen Milchick added 14 and Shepyrd Murdough finished with 11. Campbell (6-6) received 15 points from Keegan Mills, 12 from Carter Vedrani and 11 from Brendan Rice.

Alvirne 64, Trinity 49: In Hudson, Jack Dewitt tossed in six of Alvirne’s nine 3-pointers and finished with a game-high 22 points. Alvirne (4-6) received 14 from Liam O’Neil and nine from Meshack Mugariri. Royce Williams led Trinity (1-9) with 18.

Bishop Guertin 42, Merrimack 37 (OT): In Nashua, the Cardinals (9-2) trailed by five points with 1:54 to play, but rallied to force overtime and outscored the Tomahawks (8-3) 8-3 in the extra session. BG’s Dylan Santosuosso led all scorers with 16 points. Adam Ellis had a team-high 11 for Merrimack.

Salem 59, Timberlane 44: In Salem, Trevor DiMinico scored 22 points, John Bennett added 14 and Michael Ferrence finished with 12 to lead the Blue Devils (6-6). Kyle Ventola scored a team-high 14 for Timberlane (2-8). Bob Olson added 10 for the Owls.

Portsmouth 58, Windham 49: In Portsmouth, Kevin Cummings tossed in a game-high 19 points for the Clippers (9-2), who were without two injured starters. Joey DaSilva (11 points), Luke Schramm (eight) and Rocky Heres (seven) led Windham (6-5).