The Vancouver Canucks discovered Tuesday night why a 2-0 lead is a tenuous lead at best against the Anaheim Ducks.

Travis Moen scored 2:07 into overtime as the Ducks erased a two-goal deficit to defeat the Canucks 3-2 in Game 4 of their NHL Western Conference semifinal before a capacity crowd of 18,630 at General Motors Place.

Travis Moen, middle, whoops it up after scoring Tuesday's OT winner.
(Jeff Vinnick/Getty Images)

Anaheim leads the best-of-seven series 3-1 and hosts Game 5 on Thursday (CBC, 9 p.m. ET).

"It was my first OT winner, so it is exciting," Moen told CBC Sports.

"I will never forget it. I'll remember it until I am 85."

Rob Niedermayer kept the puck deep in the offensive zone, and it eventually ended up on Samuel Pahlsson's stick at the point.

Pahlsson took a shot with Niedermayer screening in front, and Moen potted the rebound to complete the comeback for the Ducks.

"He had a wide-open net on the stick side and found a way to get it in," Ducks head coach Randy Carlyle said.

"It is obviously very disappointing, frustrating," Canucks head coach Alain Vigneault said. "Whatever word you want."

Vancouver was clinging to a 2-1 lead when netminder Roberto Luongo kicked Chris Pronger's shot directly to Teemu Selanne, who swept in the rebound for his third goal of the playoffs with 5:42 remaining in regulation.

Canucks defenceman Sami Salo had lost his stick, so was unable to check Selanne on the play.

"We were down 2-0 and we never gave up," Moen said. "We kept shooting pucks on net with lots of traffic."

"We asked each individual if they could all be 10 per cent better for the third period and they are a very determined group," Carlyle said.

Chris Pronger led the second-seeded Ducks with one goal and one assist.

Pahlsson had two assists and Jean-Sebastien Giguere stopped 24 of 26 shots.

Giguere, winner of the 2003 Conn Smythe Trophy as top playoff performer, shared the goaltending duties with Ilya Bryzgalov in the first round, but has been stingy in four starts versus Vancouver.

Markus Naslund and Brendan Morrison scored for the third-ranked Canucks.

Mattias Ohlund had two assists and Luongo finished with 27 saves in a losing cause.

"We have done it [protected late leads] all year long and always been very good at it," Vigneault said. "I don't think we sat back.

"They had only had nine [third-period] shots and four scoring chances. But they got a couple of bounces and put them in."

Naslund strikes first for Canucks

Naslund staked the Canucks to a 1-0 lead with a power-play goal 12:55 into the contest.

Naslund tipped Ohlund's shot from the point and, when Giguere made a pad save, the Canucks captain potted the rebound for his third goal in as many games and fourth of the playoffs.

Morrison nearly made it 2-0 on a 2-on-1 break with Jan Bulis, but Giguere stopped his slapshot with his left shoulder to keep the Ducks within striking distance.

"We gave up way too many turnovers in the first period," Selanne said.

"Our execution levels left a lot to be desired in the first period," Carlyle said. "We started to play better in the second."

Anaheim had a glorious opportunity to pull even, if not pull ahead, when Josh Green of the Canucks was penalized four minutes for high sticking Selanne 6:48 into the second period.

But Vancouver's penalty killers successfully held the Ducks at bay, fending off a two-man advantage for 33 seconds as well as an extended 4-on-3 power play.

"They kept chipping away," Vigneault said. "We used up a lot of energy with our defence killing those penalties."

It remained 1-0 until Morrison tallied his first goal on a 2-on-1 break with rookie Jannik Hansen, deking to the backhand and around Giguere rather than winding up for a slapshot as he did in the opening period.

Bryan Smolinski narrowly missed putting the Canucks ahead 3-1 as he grazed the right goalpost with a shot from the slot early in the third period.

Pronger later settled a pass from Pahlsson and scored on a screen shot to Luongo's stick side to trim the deficit to 2-1 less than four minutes into the third.

It was Pronger's third goal and 10th point, tops among defencemen this post-season.

"We spent a lot of time in our zone and definitely lost a lot of the battles along the wall," Vigneault said. "It put so much pressure on our defence … as the game wore on, we weren't as sharp as we were initially."

Of note, Vancouver confirmed Tuesday that forward Jeff Cowan, who scored the double-overtime winner in Game 2, underwent knee surgery and will be sidelined indefinitely.

Cowan was hurt late in last Sunday's 3-2 setback at GM Place.

With files from Sports Network