"We came out flat,'' Porter said. "We didn't play too well in the first two periods and we had a stretch there in the second (period) where we just completely lost it.''

The second period was a disaster for the Sioux, who led 1-0 after one period on a goal by sophomore wing Ryan Duncan (Calgary, Alberta) at 14:39 of the opening period.

Maine outshot the Sioux 14-2 in the second period and blitzed them for five unanswered goals, including a 3-for-3 performance on the power play.

Power-plays goals by Teddy Purcell at 3:37 and by Josh Soares at 7:33 erased UND's only lead of 1-0 after one period.

Then goals 24 seconds apart by Keith Johnson at 11:07 and Michel Leveille at 11:31 ran Maine's lead to 4-1 before defenseman Mike Lundin closed the five-goal run with his power-play goal at 18:43.

That was more offense than the Black Bears needed heading into the third period. They are now 106-0-6 when leading after two periods dating back to Dec. 30, 2001.

The five goals given up by UND is the most the Sioux have allowed in a period at home since Minnesota State, Mankato scored five on the Sioux in the first period on Nov. 29, 2002, in a game that finished in a 6-6 tie.

Sioux sophomore wing Matt Watkins (Aylesbury, Saskatchewan) scored his second goal of the season at 15:09 of the final period, beating Maine backup goalie Dave Wilson to the short side with a hard slap shot off left wing.

Porter and freshman Hunter Bishop (Fairbanks, Alaska) drew assists on the goal. It was the first collegiate point for Bishop, coming in his third game.

Sioux junior goalie Philippe Lamoureux (25 saves) from Grand Forks was victimized by Maine's potent power play and UND's poor second period in taking the loss.

"We played a very unintelligent, slow (second) period,'' UND coach Dave Hakstol said. "Certainly throughout the period, we lacked intensity. That's a good way to get beat up a little bit by a good team and that's what happened.''

The Sioux lost sophomore standout Jonathan Toews (Winnipeg) to an injury in the second period, but the extent of the injury wasn't known, Hakstol said. Toews did not return for the third period.

It might not have mattered, the way the Black Bears put on a clinic in the second period in taking command.

"It's hard to say (what turned it around in the second period) other than we worked hard and generated some good bounces with hard work,'' Maine coach Tim Whitehead said. "It just seemed to go our way. Sometimes it's weird, how it happens. Some periods you work hard and it doesn't bounce your way. That period we worked hard and it bounced our way. That's a pretty good combo.''

Leveille, who led Maine with a goal and two assists, agreed. "Great effort from top to bottom, goalie, defense, forwards,'' Leveille said.

As solid as Maine's performance was, it was a disjointed night for the Sioux, who slipped to 3-2 overall.

"We had a decent first period, but we weren't all that sharp,'' Hakstol said. "We didn't show a lot of hockey sense tonight.''

The Sioux took 16 penalties for 43 minutes compared to 13 for 29 for Maine. While Maine was 3-for-7 on the power play; the Sioux failed on their four tries.

"We knew coming in that they were an intelligent team, with good skills and good experience and a little bit of savvy,'' Hakstol said. "And they showed that tonight. It's the first time we've seen that lack of hockey sense and lack of playmaking ability (on UND's part). That's not going to be a characteristic of this team.''

Both teams were Frozen Four semifinals last year, but neither reached the championship game.

UND is 11-5-1 overall in the series against Maine and now 6-2 against the Black Bears in Grand Forks.

The rematch is set for 7:07 p.m. Saturday.