GRAND FORKS, N.D. -- Nick Mattson's senior year of hockey started much like the season did for the University of North Dakota -- not very good.

While UND lost its season opener 5-1 at home to Bemidji State, Mattson was a healthy scratch in nine of UND's first 18 games, contributing just two assists.

But since then, No.1-ranked UND and Mattson have been on a tear. That roll continued tonight with a 5-1 victory over Colorado College in the opening game of a best-of-3 National Collegiate Hockey Conference playoff series at Ralph Engelstad Arena.

Mattson matched his career high for points in a game, contributing a goal and two assists as UND grabbed a 1-0 lead in the series to improve to 26-7-3 overall.

Mattson has not only been a defensive stalwart the last half of the season, he now has a team-leading 14 points (3 goals, 11 assists) in his last 14 games, in which his team has gone 11-2-1.

What's the difference for Mattson?

"It was really frustrating,'' Mattson said. "I knew I could help the team. When I was given the chance to go in, I was playing too passive. I decided to throw all doubts and fears out of my mind and just let it all hang loose and see what happens.''

What has happened is Mattson adds another weapon on the blue line for a defensive corps that ranks No. 1 in the nation in points as a group.

"It feels pretty good to be able to play up to the standard I think I can and help the team win,'' Mattson said.

Mattson set up senior wing Brendan O'Donnell's power play goal at 8:01 of the first period to open the scoring. That was a good omen for UND as well. UND now is 21-0-1 in games over the last four seasons in which O'Donnell scores a goal.

Mattson then cranked a slapper from the top of the left faceoff circle to make it 2-0 at 14:48 of the second period and assisted on defensive partner Paul LaDue's 60-foot goal at 4:01 of the third period to make it 4-1.

Connor Gaarder scored with four seconds left in the second period for a 3-0 UND lead and Tucker Poolman scored in the third period to close the scoring.

"A little slow start,'' Mattson said of UND's overall play. "It wasn't the prettiest game. I don't think any of us are too impressed with it.''

A few words from head coach Dave Hakstol after the first period seemed to get UND going.

"Coach Hak came in first intermission and kind of rattled our chain a little bit,'' Mattson said, "make sure we weren't too satisfied with the effort, first period. We have the luxury of having guys, especially this year more than any, when things aren't going good, we have the ability to turn the tide, more so than any other team.''

For Colorado College, facing UND in the first round of the playoffs for the second year in a row, the road woes continued for the Tigers, who have but one road win this year. CC has lost all five meetings with UND this season.

Hakstol, with the announcement today that senior center Mark MacMillian is done for the season following leg surgery last week, made changes on three of his four forward lines. The line that remained intact -- with Gaarder centering O'Donnell and Poganski -- contributed two goals and nine shots on goal, five by Gaarder.

"It took us a while to get into it,'' Gaarder said, "but at the end of the game, we played well. I don't think we were playing our best hockey early on in that game.''

UND outshot the Tigers 30-17 over the final two periods and junior Zane McIntyre picked up his 26th win of the season by stopping 21 of 22 Tiger shots. The Gaarder line set the pace, as they have done for a while now for UND.

"His line has been consistent,'' Hakstol said. "They're a hard-nosed group. They go out and play the same way every day, every shift.''

Gaarder helped fill a hole on faceoffs left by the absence of faceoff leader MacMillan by winning 13 of the 17 draws tonight to pace UND to a 36-33 edge.

Tyler Marble allowed all five UND goals in finishing with 21 saves. He was replaced midway through the third period by fellow freshman Chase Perry, son of former UND goalie Craig Perry, who stopped all 10 shots he faced.

Game Two starts at 7:08 p.m. Central on Saturday night.

UND notes: UND was 1-3 on the power play, CC 0-4 ... Luke Johnson's six shots on goal led UND, one more than Gaarder ... The game drew 10,824 ... Sophomore defenseman Gage Ausmus blocked a school-record nine shots for UND.

Virg Foss covered UND hockey for 35 years for the Grand Forks Herald. Since his retirement, he's in his 10th season of reporting on UND home games exclusively for UNDsports.com.