The Calgary Roughnecks' sudden slide continued Saturday night at the Saddledome, blowing a shot at a home playoff game with a 17-7 home loss to the Colorado Mammoth.

With Portland winning earlier tonight to clinch the Western Division title, the Riggers and Mammoth were playing for the right to host the other in a division semifinal next weekend.

Calgary appeared determined enough early on, rebounding from a opening-minute goal by Colorado's Nick Carlson to take a 2-1 lead five minutes in (Jeremy Cheyne, in his NLL debut, and Kaleb Toth), then holding firm to carry that lead to the second quarter.

Ben Prepchuk tied the game two minutes into the new period, but Lewis Ratcliff restored the Roughnecks' lead 100 seconds later.

Colorado replied with the next three goals -- Chris Gill, right off the faceoff after Ratcliff's goal; Brian Langtry, assisted by Carlson; and Dan Stroup, off a feed from Gavin Prout.

Toth cut the Mammoth lead to 5-4 late in the half, and Jason Wulder tied the game 36 seconds into the third quarter.

And that's when the black gold dried up for the Riggers.

Langtry regained the lead for Colorado at 1:18, Gill scored a minute later, and Langtry struck again a minute after that.

Josh Sims scored with seven minutes left in the third period, and at 9-5, the rout was on.

Kevin Dostie ended the Colorado run 28 seconds, but the Mammoth soon started a new one -- three goals in the final 2:39 of the quarter, making the score 12-6.

Cheyne scored to open the fourth quarter, and Colorado just came back for more. Gavin Prout. Sims. Jay Jalbert. Langtry. Gill.

Embarrassment.

Three of the last five goals came on the power play, as Calgary lost its cool repeatedly. Wulder was tossed for an illegal cross check, and the league has a mountain of incidents to examine in the days ahead.

Just more bad blood in the Western Division's version of the Hatfields and the McCoys.

The playoff game, by the way, is next Saturday night at Pepsi Center. Look out.