BOSTON - The Vancouver Canucks are heading home in search of answers after letting the Boston Bruins back in the Stanley Cup final.

Tim Thomas was unbeatable and Rich Peverley scored twice Wednesday as the Bruins steamrolled Vancouver 4-0, making the NHL's best regular-season team look ordinary for the second straight game and tying the series 2-2.

"Every time we've faced adversity as a team we've rose to the challenge," Thomas said. "We needed to do that one more time because we were down 2-0 and we've done that for two games. The challenge for us is that we need to keep doing that."

Boston outscored the Canucks 12-1 in the two games at hostile TD Garden. Alain Vigneault removed starter Roberto Luongo after he surrendered four goals on 20 shots in Game 4 and will now face more questions about whether Luongo or backup Cory Schneider will start Game 5 at Rogers Arena on Friday.

"It was a tough one," said Luongo. "Three of the goals went off something and in. Obviously, we're not getting the breaks so it's just a matter of staying focused. We've got home ice advantage for a reason."

Vigneault stood by his starting goaltender after the game.

"Lou's going to be fine," Vigneault said. "He's one of the best goaltenders in the league and we have a lot of trust and faith in his ability to play well."

Even if Luongo rebounds, goaltending is far from the only question hovering over the team.

A once potent power play has disappeared as Vancouver failed to convert on six more opportunities and now sits at just 1-for-22 in the series. Two of those situations came in the first period when the Canucks were unable to solve Thomas and grab early momentum.

"We've got to solve Thomas, that's the thing," Canucks captain Henrik Sedin said.

The team's star players have yet to make much of an impact in the series. Ryan Kesler, who generated Conn Smythe talk heading into the series, has just one assist in four games — which is one more Sedin.

The Bruins have been getting contributions throughout their lineup with goals from Michael Ryder and Brad Marchand to go with the pair scored by Peverley.

Thomas has been the best player in black and yellow, allowing just five goals on 146 shots in the series. He made another 38 saves in Game 4.

"Anyone who knows the story of Tim Thomas, he's taken a real bumpy road to get to the NHL," said Bruins coach Claude Julien. "He's had so many obstacles to overcome. It makes him a battler, it makes him the perfect goaltender for our organization."

Julien won his 31st playoff game behind the bench with the Bruins, tying the franchise record set by Don Cherry.

With Canadian Prime Minister Stephen Haper watching from the stands, the Canucks were undone by a poor second period for the second straight game. Goals 2:18 apart by Ryder and Marchand just past the midway point of the game gave Boston a 3-0 lead and elicited derisive chants of "Luuuuuongo" from the energized TD Garden crowd.

The goaltender could have used more help from his teammates.

Ryder's goal at 11:11 came on a long wrist shot that was only dangerous because defenceman Sami Salo was reaching and had it deflect off his stick. Marchand roofed a backhand shot at 13:29 after Keith Ballard was unable to control the puck and Henrik Sedin left him open in front.

During the series, Vancouver has been outscored 8-0 in the middle period.

Another troubling trend is the lack of pushback the Canucks showed after falling behind, losing a number of battles for the puck against a more determined Boston team.

The night got off to a roaring start when Bruins legend Bobby Orr was shown on the scoreboard waving a Nathan Horton flag prior to the game. Horton was knocked out of the series with a concussion by a dangerous hit from Vancouver's Aaron Rome in Game 3.

Peverley, the man who replaced Horton on Boston's top line, opened the scoring at 11:59 of the first period. He took a nice chip pass from David Krejci before racing in alone and sliding the puck through Luongo's legs.

Julien said Peverly responded to the pressure of being elevated to the top line.

"I like his character, he comes to play every day," Julien said. "He's a very serious athlete, he takes care of himself and right now he's being rewarded."

Vancouver had a number of good opportunities to tie it but couldn't solve Thomas, who was at his aggressive best challenging shooters and fighting for position in the crease. He denied a charging Maxim Lapierre towards the end of the period and managed to control the rebound.

Some signs of frustration started to emerge from the Canucks, who had their passionate fanbase partying into the night after taking the first two games of the series on home ice. Henrik Sedin took a long pause before skating to the penalty box after being called for high-sticking early in the third period, giving referees Dan O'Halloran and Kelly Sutherland an earful on the way by.

Peverley's second goal chased Luongo at 3:39 of the third period. He skated hard to the goal and had the puck ricochet in off him after Luongo tried to break up a pass through his crease.

With Schneider entering the game, Bruins fans chanted "We want the Cup! We want the Cup!" — the same thing the Canucks heard at Rogers Arena after Game 2.

The series is now down to a best-of-three. One of the few positives for Vancouver is they don't need to find a way to win in the hostile confines of TD Garden — two more victories on home ice will do the job.

"We worked hard all year to get home ice advantage and this is where it's going to serve its purpose," Luongo said. "We want to make sure that we get playing the way we did in the first two home games and establish a good tempo and take it to them."

Notes: Tanner Glass replaced Jeff Tambellini in Vancouver's lineup ... Bruins forward Marc Savard, out for the season with a concussion, was given a loud ovation when he was shown on the scoreboard in the first period ... NBA star Steve Nash attended the game. His brother-in-law is Canuks forward Manny Malhotra ... Announced attendance was 17,565.