The Halifax Mooseheads aren't ready to sit back now that they are the first team guaranteed to advance at the Memorial Cup.

Antoine Morand opened the scoring and Raphael Lavoie potted a highlight-reel goal that put Halifax ahead for good in a 4-2 win against the Guelph Storm on Sunday.

The Mooseheads, who have opened the four-team tournament with back-to-back wins, are assured at least a spot in the semifinal regardless of the outcome of their last round-robin game against the Rouyn-Noranda Huskies. A third straight victory would send them directly to the championship game.

"We played good the first two games but we have one more and we're focused on that," said Morand.

"We're making sure we play the 'Moose' way and I think we did that."

Maxim Trepanier and Samuel Asselin also scored for the host Mooseheads while Alexis Gravel stopped 33 shots for the win.

Sean Durzi had both goals for the Ontario Hockey League champion Storm as Anthony Popovich made 38 saves in defeat.

WATCH | Mooseheads moving on after weathering the Storm:

The Halifax Mooseheads improved to 2-0 at the Memorial Cup, beating the Guelph Storm by a 4-2 final. 1:54

Guelph forward Liam Hawell had the game's first true scoring opportunity while on an early power play but was turned away by Gravel with the glove hand.

That save turned out to be big when less than three minutes later Morand opened the scoring, deflecting a pass from Jocktan Chainey over the blocker of Popovich at 5:10 of the first.

The Storm didn't get rattled, however, and maintained much of the play through the opening period before finally solving Gravel in the final minute.

Durzi let go of a bomb from the point that went through a crowd and over Gravel's blocker at 19:10 to send the two squads into first intermission tied 1-1, with the shots favouring Guelph 16-8.

"Even though the amount of shots was in Guelph's favour I thought 5-on-5 we were playing pretty good," said Mooseheads coach Eric Veilleux. "Just a matter of us trying to keep it that way 5-on-5."

Guelph went on its fourth power play of the game at 5:03 of the second, but it was the Mooseheads that took advantage to regain the lead as they came out looking much different than the first 20 minutes.

Shortly after Joel Bishop blocked a point shot that left him crawling to the bench in agony, Lavoie would strike with 15 seconds still remaining on Guelph's man advantage.

NHL Draft looms for Lavoie

Lavoie, an 18-year-old draft-eligible forward, made a strong solo effort as he headed down the ice 1-on-2 while shorthanded and split the Storm defence with a toe drag before beating Popovich 6:48 into the second.

Trepanier extended the lead to 3-1 less than four minutes later when he banged home a loose puck sitting behind Popovich in the crease on a play that began with a Guelph turnover behind its own net.

"I think we did a good job staying composed with our emotion," said Morand. "Guys were skating the puck and giving the forwards a good opportunity to attack."

The Storm took three straight minor penalties after falling behind two goals and gave Halifax 1:22 of 5-on-3 time that led to Popovich having to bail him teammates out more than once.

Halifax was outshooting Guelph 17-5 up to that point in the second and was ahead in shots 28-25 entering the third.

Guelph finally made good on its fifth power play when Durzi struck for the second time just 1:07 into the third to make it a one-goal game, but Asselin responded six minutes later on his own rebound to send the pro-Mooseheads crowd of 10,036 into a frenzy.

"Not our best night by any stretch, mismanaged the puck, lost puck battles and foot races," said Storm head coach George Burnett.

"We had an opportunity early in the third but our club didn't respond the way we had been responding in the playoffs."

Late in the game the Storm had one final power-play opportunity and could have pulled Popovich for a 6-on-4, but Burnett didn't want to take the chance of being scored on when goal differential could dictate who advances.

"A one-goal deficit, may have considered it but we didn't have the puck near enough most of the evening and we didn't think the goal differential was something we should be playing around with at that point in time," said Burnett.

Halifax opened the tournament with a 4-1 win over the Western league champion Prince Albert Raiders while Guelph beat the Quebec league champion Huskies 5-2 to open its tournament.

Rouyn-Noranda and Prince Albert, ranked No 1 and No. 2 respectively in the Canadian Hockey League meet Monday.