For Sean Greenhalgh, his NLL debut literally was a tale of two halves.

In the first half his shots couldn't hit the net, but in the second half, Greenhalgh scored four goals, helping the Wings to a penalty filled 13-11 victory over the Colorado Mammoth Friday night.

A Pepsi Center crowd of 15,726 witnessed the NLL coaching debut of Colorado's Gary Gait, whose number 22 was retired prior to the game, the opener of the 20th season of professional indoor lacrosse.

Typical of a season opener, both teams looked sluggish early on. Dan Finck scored the first goal of the 2006 season three minutes in, giving the Wings a 1-0 lead. The lead wouldn't last long, as Colorado tied the game on an acrobatic rebound shot by Brian Langtry at 4:13 of the quarter.

Gavin Prout gave the Mammoth its first lead of the night at 7:10, but the Wings tied the game on a Rob Van Beek goal moments later.

A few minutes after that, during a four-on-four sequence (Van Beek and Colorado's Jay Jalbert in the box), Wings coach Lindsay Sanderson pulled goaltender Matt Roik for a man advantage. Unfortunately, this backfired as Gee Nash, after making the save, lobbed the ball downfield for an empty net goal and a 3-2 Colorado lead.

Prout's second goal of the night, this one on the power play with Shawn Nadelen off for holding, ended the first quarter with the Mammoth up 4-2.

Colorado boosted its lead to 7-2 six minutes into the second, on Dan Carey's first NLL goal, Chris Gill's first goal with Colorado, and a penalty shot goal for Prout (completing his hat trick).

Luke Wiles ended the Colorado scoring spree with his first professional goal, at the 9:39 mark. With play beginning to get chippy between the long time rivals, Philadelphia added goals from Dan Marohl and a late-arriving Jeff Ratcliffe to pull to within 7-5 at halftime.

It was nearly 8-5, though, as a shot by Ben Prepchuk went in the net just after time had expired -- a good omen for the surging Wings.

Wiles scored again to open the second half, but the Wings soon went down two men on penalties to Jeff Spano and Glenn Clark.

A number of big saves by Roik kept Colorado off the board and Keith Cromwell tied the game, 7-7, just as Clark was coming out of the box.

However, Colorado regained the lead on goals by Prepchuk, Jalbert and Nick Carlson over the next four minutes, but it was the final lead for the Mammoth.

Philadelphia fired off six straight goals across the third and fourth quarters for a 13-10 lead, a streak started and finished by Greenhalgh.

Jalbert scored with 1:16 left, ending the scoring but not the action. Following the final whistle, a skirmish took place at midfield, with penalties to Roik, teammate Thomas Hajek and Colorado's Dave Stilley, concluding a night with 119 penalty minutes between the two teams.

Greenhalgh topped the Wings with seven points (four goals, three assists), and Prout led the Mammoth with five points (three goals, two assists).

The Wings now travel to Minnesota to face the Swarm on Friday, 6 January, while the Mammoth hosts Rochester the following night.