AUGUSTA — Third-seeded Oceanside overcame a poor first quarter and held on in the closing minutes of its Class A North boys’ basketball quarterfinal Saturday, posting a 53-49 win over sixth-seeded Nokomis at the Augusta Civic Center.

Nokomis (11-8) couldn’t get a good look at the basket on two late possessions with a chance for a go-ahead bucket, and Oceanside’s Cooper Wirkala made a pair of free throws with less than three seconds remaining.

Michael Norton Jr. scored 27 points for Oceanside (16-3), the reigning regional champion.

Josh Smestad led Nokomis with 22 points, while Zach Hartsgrove added 17.

Nokomis took command early, racing out to an 18-8 first-quarter advantage, but led by a scoring surge from Norton, the Mariners fought back. Oceanside was up 24-22 at halftime, and then 40-35 after a fast-paced third quarter.

Nokomis wasn’t deterred, fighting back to take a 44-42 lead on a layup in traffic by Smestad with 3:45 remaining.

“I love it,” Smestad said of playing in the clutch. “That’s kind of been my role. … They have a lot of confidence in me and that really brings (out) the confidence in me. I know they trust me, and I can finish and I can do what I need to do.”

Oceanside answered, as a Norton basket put the Mariners up 46-44. Norton fouled out moments later, but Oceanside still was in front 51-49 with 22 seconds left. Smestad drove into the paint but had to settle for a floater that was off the mark, leading to an Oceanside rebound and trip to the free-throw line.

Trevor Reed missed both shots, giving Nokomis another chance with 13 seconds left. Hartsgrove tried a jumper from the wing that the Mariners contested, and it grazed off the front rim.

“They missed a couple free throws, and you’re thinking ‘Here’s some tournament magic, here’s the first buzzer-beater of the tournament,'” Nokomis Coach Ryan Martin said.

After falling behind in the first quarter, Oceanside got six points apiece from Norton and Jack Lombardo in the second quarter and took the lead by halftime.

“We didn’t do all that we had talked about,” Oceanside Coach Matt Breen said of his team’s slow start. “We had some people switching, some people not switching, and they were just getting some easy buckets. … They really started to pick up the defense playing as a unit.”

Oceanside’s semifinal opponent Wednesday will be seventh-seeded Cony (11-9), which upset No. 2 Hampden Academy, 60-48.