Nate Schmidt normally doesn't have trouble sleeping before games. His pregame nap typically lasts a few hours, but he found himself staring at the ceiling Saturday afternoon before the Gophers faced Boston University.

"Your mind is racing," the sophomore defenseman said.

Schmidt figured shuteye wouldn't come any easier that night as he readied himself to play a hated rival with a trip to the Frozen Four at stake.

"It's going to be tough," he said.

Can you blame him? The hockey gods smiled and handed fans a gift when the Gophers and North Dakota both won their opening NCAA West Regional games, setting up their sixth and final meeting of the season on Sunday and a rematch of their topsy-turvy showdown in the WCHA playoffs a week ago.

North Dakota won that game 6-3 after climbing out of a 3-0 hole. The Gophers controlled the first 30 minutes, fell apart in spectacular fashion in the third period and then had to hear about their collapse in the days leading to Saturday's opening game in the NCAA tournament.

"It made us a little bitter in practice," sophomore center Nick Bjugstad said.

The memory adds extra spice to a rivalry that doesn't require additional motivation. These are two programs rich in tradition with passionate fan bases and a mutual disdain for each other. Sunday marks their 288th career meeting, and that alone is motivation enough.

But along with bragging rights, the winner will advance to Tampa for the Frozen Four, while the loser is forced to stew until they meet again next season.

"I don't think words can describe it," Gophers sophomore center Erik Haula said. "It's something that doesn't happen that much."

It should be a lively atmosphere, although the vibe inside Xcel Energy Center was anything but that Saturday. The building was half full -- attendance was announced at 9,386 -- and lacked any real sustained energy. That presumably will change as Gophers and Fighting Sioux fans mingle.

"There's nothing like playing North Dakota for us," senior captain Taylor Matson said.

The Gophers hold a 3-2 advantage this season, but their previous meeting looms larger than the rest. The Gophers said all the right things in response to their collapse last week. They practiced the next day, talked about what went wrong and vowed publicly and privately to put it behind them.

"We tried to drop that out of our brains," Matson said. "We just wanted to get it out of our system."

They are human, however, and it's not easy to erase the gory memory of allowing five goals in one period after being in such control of things. That sort of disappointment tends to stick, no matter how much everyone preaches the need to move on.

"You've got to kind of forget about it, but obviously it's still in the back of our mind a little bit, which is good for us," Bjugstad said. "I think it will motivate us a little more."

That's a delicate thing though. The Gophers naturally were frustrated by how they came unglued in that third period and hope to atone for that with a strong showing. But Schmidt said they also must "harness their energy." In other words, they can't go crazy trying to make up for one bad period.

"You've got to take a little bit of revenge but also be calm, cool and collected," he said. "If you get too amped up or too excited or too far into the rivalry, it can kind of take you away from our game."

In the wake of last week's loss, Gophers coaches stressed the importance of responding in tough times. Coach Don Lucia used a boxing analogy, being able to take a punch and keep going.

The Gophers showed some of that trait in a 7-3 victory against Boston. They responded every time Boston did something to grab momentum. The Gophers didn't stay on their heels and allow things to snowball.

"I think we learned something from last weekend," Haula said.

The stakes are much higher this time. It's win or go home for two rivals that don't particularly like each other.

"It doesn't get much better than that," Schmidt said.

Well put.

Chip Scoggins • ascoggins@startribune.com