MANCHESTER — Defense matters, and it matters most late in the season.

That point was driven home in Wednesday’s Division II semifinals at Gill Stadium, where the second-seeded Goffstown High School baseball team trounced third-seeded Portsmouth 9-2.

The Grizzlies (18-3) turned two double plays in the victory, and the Clippers didn’t give themselves much of a chance by committing nine errors.

“I told them before the game whoever makes fewer mistakes is going to win,” Goffstown coach Adam Lawrence said. “Defensively we did the job.”

The bottom of the sixth typified the type of game it was for Portsmouth (15-4). Goffstown’s first four batters in the inning reached on errors, and the Clippers made five miscues overall. The costliest mistake came when Tanner Putnam lined a ball to center field with the bases loaded. The ball deflected off the top of Kobie Taylor’s glove and rolled to the wall, allowing Putnam — and three other runners — to score on the play.

Connor Easton also scored on an error in the inning, which pushed Goffstown’s lead to 9-1.

“There’s no explanation for it,” Portsmouth coach Tim Hopley said. “So many uncharateristic things, and it’s not like us. It’s not. We usually execute in those situations and today we didn’t.”

Right fielder Cam Bond had three hits for the Grizzlies, who also received two hits from both center fielder Mike Bailey and first baseman Connor Easton.

Tanner Putnam pitched a complete game to collect the win. He surrendered nine hits, walked two and struck out two.

“Putnam battled,” Lawrence said. “The kid’s a bulldog.”

Goffstown will face top-seeded Windham in Saturday’s championship game, which will be played at Northeast Delta Dental Stadium and is scheduled to begin at 4 p.m. Windham beat fourth-seeded Coe-Brown 6-3 in Wednesday’s second semifinal.

Goffstown scored two unearned runs in the first inning, and doubled its lead when third baseman Kyle Perron hit a two-run home run to left in the third. Portsmouth committed four errors in the first three innings.

Taylor, Josh Saurman and Justin Lent each had two hits for the Clippers, who scored a run in the fifth and one in the seventh.

It was the third postseason meeting between the two programs in as many years. Portsmouth beat Goffstown in the 2013 championship game, and the Grizzlies defeated the Clippers in last year’s semifinals.

“There are good baseball players all throughout that dugout,” Hopley said. “I don’t think the moment was too big for us. I just shrug my shoulders and shake my head.”