After seeing their three-goal lead evaporate, the Portland Winterhawks' quick-strike offence ensured the race for the MasterCard Memorial Cup title is still wide open.

Derrick Pouliot and Chase De Leo scored 23 seconds apart in the third period Monday as Portland picked up its first win at the tournament with a 6-3 victory over the London Knights before a crowd of 7,575 at Credit Union Centre.

The result means that all four teams at the Canadian Hockey League showcase now sit with 1-1 records and guarantees a tiebreaker game on Thursday.

The Winterhawks, who were coming off a 7-4 loss to the Halifax Mooseheads of the Quebec Major Junior Hockey League on Saturday in a game that saw Portland blow a 3-1 lead, responded well after surrendering a similar edge against the Knights.

"It was a big win for our team. We needed to respond with a good effort," said Winterhawks coach Travis Green, whose team led 3-0 midway through the second period before London stormed back. "That's a real good hockey team we played over there. It was a hard-fought win and I'm happy with how our team played."

Ty Rattie had two goals and an assist for the Western Hockey League champions, Saskatoon native Taylor Leier had a goal and two assists, and Oliver Bjorkstrand chipped in with a goal and an assist.

"I thought we had a really good start to the game and then we kind of let off the gas a bit, which we've done a couple times this post-season," Portland defenceman Seth Jones said. "We've got to stop that. They got back in it but we were able to get a couple more goals and hold the lead."

Mac Carruth made 25 saves for the Winterhawks after allowing all seven goals in the loss to Halifax.

"Maybe he'd like to have that first game back. We have total confidence in him," Pouliot said. "It was good to see him play well tonight and we're going to need that going forward."

After London tied the game 3-3 early in the third period, Pouliot, a first-round pick of the Pittsburgh Penguins in 2012, ripped a shot off the shoulder of Knights goalie Anthony Stolarz and in on a Portland power play at 6:20. De Leo ended the London netminder's night at 6:43 by sliding a shot home from the slot.

"We have to contribute every once in a while and do the little things and just do whatever it takes to help the boys win," said De Leo, who plays on Portland's checking line. "It felt good to finally get one on the board."

Bo Horvat and Alex Broadhurst replied with a goal and an assist each for London, while Scott Harrington also scored. Stolarz allowed five goals on 26 shots before being replaced by Jake Patterson.