Wyatt Grondin scored a power-play goal 3:21 into the second overtime period to lift seventh-ranked Scarborough High to a 5-4 victory over No.3 South Portland/Freeport/Waynflete in a Class A boys’ ice hockey semifinal at the Cross Insurance Arena Tuesday night.

Grondin took a loose puck at the left post and tucked it in, starting a wild celebration for the Red Storm.

Scarborough (12-8-1) will face Thornton Academy in the Class A state championship game at 3 p.m. Saturday at the Cross Arena. South Portland finished 13-7-1. The Red Storm lost in overtime to Lewiston in the 2020 state game.

It was back-and-forth in the first overtime, with both teams having great chances to score. South Portland’s Cullen Adams had a breakaway stopped by Scarborough goalie Keegan Weed. Then the Riots’ Jasper Curtis made a sliding save on Scarborough’s Will Fallon with 8.4 seconds left.

It was a wild third period, which began with South Portland/Freeport/Waynflete ahead 2-1.

South Portland took a 3-1 lead just 47 seconds into the third on a power-play goal by Ian Wright. Scarborough responded with three goals in eight minutes. Olin Pedersen got the first one. Then with 8:38 remaining, Billy Mahoney tied it at 3-3 with a short-handed breakaway goal.

The Red Storm went ahead 4-3 with 5:23 left on Jack Matthews second goal of the game. Wyatt Grondin took a shot from the right point that was wide. The puck came off the backboards to Matthews on the left and he tucked it inside the post.

The Riots tied it at 4-4 with 4:40 left when Roan Hopkins scored his second goal of the game off a face-off in the left circle.

After a scoreless first period, the teams scored three goals in the first 5:15 of the second.

Scarborough got the first one, scoring on a carryover power play when Matthews tucked the puck inside the left post just 12 seconds into the second. Toby Lappin tied it at 1 with 11:01 left in the second. Then Hopkins put the Riots ahead 2-1 just 67 seconds later.