The Penguins raced into a 3-0 lead in the first period of the so-called Battle of Pennsylvania thanks to goals from Sidney Crosby, Tyler Kennedy and Pascal Dupuis.

Danny Briere pulled one back in the second, then added another in the third before Brayden Schenn levelled things up with 7:37 of regulation to play - and Voracek won it in OT.

Late show

The Los Angeles Kings scored twice in the last five minutes to claim the early advantage over 2011 finalists and Western Conference top seeds the Vancouver Canucks with a 4-2 victory.

Dustin Penner and Dustin Brown scored the crucial goals for the Kings. Mike Richards and Willie Mitchell had earlier scored powerplay goals for Los Angeles, while Alexandre Burrows and Alexander Edler tallied for the Canucks.

Rookie Gabriel Bourque scored twice to lift the Nashville Predators to a 3-2 win over the Detroit Red Wings.

The 21-year-old put the Predators 3-1 ahead after Henrik Zetterberg had cancelled out Paul Gaustad's opener. Tomas Holmstrom pulled another back late on but it was not enough for Detroit, who will get a chance to level the series on Friday night.