TORONTO — Intent on playing a physical style, the Toronto Maple Leafs need better penalty killing to keep it from backfiring.

Undisciplined penalties resulted in three power-plays goals for the Pittsburgh Penguins on Saturday night — two of them by Sidney Crosby — in Toronto's 5-2 loss to the defending Stanley Cup champions.

There was plenty wrong all-around for the Maple Leafs (0-3-1), but the porous penalty killing was one area that particularly stood out. Crosby's goals, both set up by Evgeni Malkin, came in the second period for a 4-1 lead that erased any hopes the Leafs might have had of mounting a comeback.

"There are a lot of things we have to do better," Maple Leafs coach Ron Wilson said. "Clearing pucks is No. 1. ... I've never done it, but we have to somehow practice shooting the puck down the ice, because we just aren't very good at it."

Jordan Staal, Matt Cooke and Sergei Gonchar also scored for the Penguins (4-1-0), who were coming off a grinding 5-4 win over Philadelphia on Thursday night as they continue a grueling stretch of five games in eight days. Marc-Andre Fleury stopped 18 shots to remain unbeaten.

"When you win the special teams, it was 3-0 for us tonight, that's a good recipe," Penguins coach Dan Bylsma said.

Niklas Hagman and tough guy Jay Rosehill, with the first of his career, replied for the Maple Leafs, who were game with the rough stuff but brought little else.

"It is depressing here right now," Wilson said. "We've got to find a way to get some momentum early in the game."

Vesa Toskala made 28 saves but looked uncomfortable in goal in the first period, and received plenty of mock cheers from a disgruntled crowd of 19,374. With the penalty killing problems, another focal point must be their discipline, as a few key momentum changes were given back by ill-timed penalties.

The Penguins led 2-0 and were up 14-2 in shots after 20 minutes, and if not for a pair of fights — Colton Orr handled Eric Godard and Jamal Mayers bloodied Craig Adams — the Maple Leafs would have been totally invisible.

Cooke opened the scoring a minute after the Orr-Godard bout, whipping a wrist shot over Toskala's glove from the slot at 3:20. Tyler Kennedy set the play up by stripping Jason Blake of the puck in the slot.

The Pens went up 2-0 at 10:23 when Gonchar slid a point shot through Toskala's legs, capitalizing on a roughing penalty assessed to Orr for jumping Cooke at 8:51.

"Occasionally you need a save," Wilson said.

Two seconds after Gonchar's goal, Mayers took down Adams.

Rosehill gave the Leafs some life by shovelling in Mayers' centring pass at 2:01 of the second period, but a silly offensive-zone holding penalty by Matt Stajan 16 seconds later put that momentum on hold.

Fifteen seconds after that, Crosby picked up the rebound off a Malkin shot as it came off the boards and slipped it into an empty net.