Defense was the difference for Jackson and Arlington as they qualified for regionals and advanced to the Northwest 4A District title game.

SNOHOMISH — Jackson’s undefeated season was never in jeopardy Friday night at Glacier Peak High School.

Junior guard Dan Kingma opened the game with a three-pointer and the Timberwolves led for the duration, beating Mount Vernon 66-37 to reach the championship game of the Northwest 4A District boys basketball tournament.

Third-ranked Jackson (22-0), which locked up a spot at regionals, will face Arlington next Friday for the district title. Arlington beat Edmonds-Woodway 58-47 in the other tournament semifinal.

Three Timberwolves were in double digits, with Jason Todd and Brian Zehr scoring 21 and 20, respectively. Connor Willgress added 11.

But Jackson’s defense is what resonated most with coach Steve Johnson.

“This is a team that you really need to guard well,” he said of Mount Vernon, “because they could put five double-digit scorers out there. I was really proud of the fact that we guarded really great from 22 feet in.”

Last week against Kamiak, Mount Vernon (14-8) put up 100 points and made 11 three-pointers. Jackson held that same Bulldogs team to just four points in the second quarter Friday night. Jackson didn’t allow a basket until the 2:06 mark of the quarter.

Zehr got Jackson started with 14 first-half points. With five minutes left, he also added the exclamation point on the victory when guard Kyle Graff found him for an alley-oop dunk.

“Dan (Kingma) set the back screen for me and I saw an opening, and I just waited to go up and get it,” Zehr said.

Other semifinal

Arlington 58, Edmonds-Woodway 47

Arlington (20-2) led most of the game, but Edmonds-Woodway (14-8) hung around and made some runs. The Warriors trailed by only a point after a Gavin Smoke three-pointer at the halftime buzzer.

Before Eagles coach Nick Brown could get into the locker room to motivate his team for the second half, captains Terry Dawn and A.J. Passalaqua beat him to it.

“I heard them in there yelling pretty good,” Brown said, “which is good, because I’ve been waiting for that.”

Arlington played stellar second-half defense, particularly down the stretch.

Dawn got a steal and completed a three-point play to give Arlington a five-point lead with 5:35 left. He came up with another steal on the Warriors’ next possession, leading to a Kaleb Bryson three-pointer.

“Our guards really put ball pressure out,” Brown said.

Bradley Brummel scored 16 points, Bryson 12 and Dawn 11 for the Eagles. Devin Joseph led E-W with 13.