Alexandria coach Ian Resch forgot about the significance of his team's victory until reminded in the locker room.
The Cardinals won their first state tournament quarterfinal game in program history, edging Thief River Falls 1-0.
No. 4 seed Alexandria (18-10-1) was 0-4 in its previous tournament openers.
Jack Westlund broke a scoreless tie with a goal at 3 minutes, 7 seconds of the second period. Andrew Revering fired a pass to the backdoor for Westlund to tap high into the Thief River Falls goal.
"He hit my stick," said Westlund, who also scored in the second overtime of the Section 6 championship. "I pretty much just stood there."
Also deflecting credit was goaltender Jackson Boline. He finished with 19 saves but lauded his defenders for their willingness to block shots.
Team defense and Boline's steady approach kept Thief River Falls scoreless.
No. 5 seed Thief River Falls (16-11-2) tried to draw even on a 5-on-3 power play at 2:19 of the third period. The Prowlers called timeout and won the faceoff in the Cardinals zone but could not capitalize.
"It just wasn't happening tonight," Prowlers coach Tim Bergland said. "It's credit to them, but also we didn't execute. A couple of our better players were walking through the slot but didn't finish."
Alexandria defenseman Jack Powell said the key penalty kill sprang from a proper mind-set: "It starts with confidence and knowing each guy will get to his spot and get the puck out."
DAVID LA VAQUE