In a 1-1 game early in the second period, Warroad had a two-minute 5-on-3 advantage. The Warriors didn't capitalize.
Coach David Marvin said he thought it might lead to a letdown for his team.
"I really thought there was a big opportunity for the other team to have momentum," Marvin said.
Instead, the Warriors took a 2-1 lead 1 minute, 44 seconds later on the first of freshman Geno Hendrickson's two goals in the game. Five more goals followed for the top-seeded Warriors in a 7-1 victory over Alexandria in their Class 1A semifinal on Friday at Xcel Energy Center.
Hendrickson was one of three players who each scored two goals for Warroad. The others were sophomore Hannah Corneliusen and junior defenseman Kaitlyn Kotlowski, whose first goal was a point shot through traffic for a 3-1 lead.
"It was a power-play goal, and it's been a while since I've had one," Kotlowski said.
The bright spot for the fourth-seeded Cardinals (21-8) came when they struck first with a goal from freshman Anna Doherty on the team's third shot on goal in the first period.
"We just didn't come ready to play tonight," Alexandria coach Molly Arola said. "Just weren't able to bring our A-game physically and mentally."
Warroad (24-3-2), winner of 12 consecutive games, returns to the title game for the first time since it won back-to-back championships in 2010 and 2011.