TORONTO -- Roaring cheers greeted the announcement of Jonathan Bernier as the Toronto Maple Leafs' starting goaltender. His return from injury was desperately needed amid a season-worst losing streak.

Bernier came back from a five-game absence and did what he could against the potent Blues. But the result was the same as recent efforts for the Leafs, who made too many mistakes in front of him and couldn't come back, dropping their sixth straight, 5-3 to St. Louis on Tuesday night.

The loss, coupled with the Columbus Blue Jackets' 4-2 victory over the Detroit Red Wings, dropped the Leafs out of a playoff spot for the first time since Jan. 14. Toronto is 10th in the Eastern Conference behind the Red Wings, Blue Jackets and Washington Capitals, who all have 80 points, because it has played the most games.

"Certainly we're afraid of letting it slip away," said winger Joffrey Lupul, who scored the Leafs' first goal. "The whole year we've thought we were a playoff team, and we still believe that now. ... Realistically we're still right there with these other teams."

Bernier, who stopped the first 20 shots he faced and 44 of 48 overall, said nothing should have to be said inside the locker room.

"If we're missing motivation, at this time of the year everyone should have some," he said.

In his first game since aggravating a groin injury March 13, Bernier even played with a rare early lead before the Blues broke through.

Blues captain David Backes had a hat trick (counting the empty-netter) and U.S. Olympic hero T.J. Oshie and former Leafs forward Alex Steen scored once apiece against Bernier, who fell victim to a failed clearing attempt by Dion Phaneuf and other blunders.

Lupul scored early and then Carl Gunnarsson and James van Riemsdyk had goals in the third period for the Leafs (36-30-8), who had the building buzzing late.

Ryan Miller ultimately made the necessary stops, finishing with 21 to improve to 32-15-3 in his career against Toronto.

With the victory, the Blues (49-16-7) hit 105 points to pass the Boston Bruins for the top spot in the NHL. They've won 10 of 13 games since acquiring Miller and forward Steve Ott from the Buffalo Sabres before the trade deadline.

In the process, St. Louis added to the woes of the Leafs, who were second in the Atlantic Division and third in the Eastern Conference the last time they won a game.

Improving their starts was a major point of emphasis for Toronto. It worked when Bernier helped withstand an early barrage before the Leafs scored first for the first time since March 10 at the Anaheim Ducks, which was seven games and six losses ago.

With 2010 Canadian Olympic forward Brenden Morrow in the box for high-sticking, the Leafs' second power-play unit cashed in. After getting robbed by Miller at the side of the net, Nazem Kadri had the quick reaction skills to bat the puck out of the air and right to Lupul at the side of the net for his 19th of the season at 11:30 of the first period.

The Leafs' lead didn't last long, as Oshie, who gained fame and the "T.J. Sochi" nickname for his shootout brilliance at the Olympics, tipped a shot from Roman Polak down and dived to knock the puck in at 15:55.

Had the Leafs been able to keep the score tied 1-1 by the first intermission, they might've been able to make it a game. Instead, van Riemsdyk took an ill-advised interference penalty in the final minute to set up a memorable miscue by Phaneuf.

With a chance to send the puck down the ice on the penalty kill, Phaneuf wound up twice and held onto it just long enough for Oshie to poke it away. Seconds after the turnover, Backes beat Bernier clean with 32.3 seconds left.

The Blues' 23 first-period shots were the most the Leafs have given up this season.

Considering that, their second period was a strong improvement. Unlike the first, when they were hemmed in their own zone and needed Bernier to make big save after big save, the Leafs opened things up on the Blues and traded some chances.

They couldn't cash in, but the deep, balanced Blues did, as Backes scored his second of the night at 7:32 after a brilliant pass from Alex Pietrangelo.

At 17:35, St. Louis added the dagger when Steen beat Phaneuf in a net-front battle and then flipped a back-hand shot past Bernier for his 31st goal of the season.

Down 4-1, the Leafs got some life 4:39 into the third period when Pietrangelo turned the puck over to Gunnarsson, who blasted a shot by Miller to cut the deficit to two.

Van Riemsdyk's goal at 15:54 provided even more hope, but that was extinguished on Backes' empty-netter.

NOTES -- With Bernier back, the Leafs sent goaltender Drew MacIntyre back to the AHL's Toronto Marlies. ... Defenceman Paul Ranger was scratched for the third straight game with a neck injury.