Everyone loves a good underdog story.

So far, it's hard to argue the Calgary Flames aren't exactly that in the NHL: as big a surprise success as we've seen early in a season.

They're the Rudy Ruettiger of the quarter-way mark (which the league hits on Saturday).

Few expected much out of the Flames this year, not with so many young players on the roster and not with what was believed to be a long, long rebuild in its early stages.

But entering Sunday's games, they sat 10th overall in the NHL and fifth in the gruelling Western Conference, on pace for a remarkable 104 points. They've scored more goals than all but four teams (3.05 a game). They have one of the best power plays in the league (22 per cent). And netminder Jonas Hiller's even strength save percentage of .936 is eighth among regular starters.

That's the good news.

The bad? It's extremely unlikely they'll be able to keep all this up.

A year ago, the Toronto Maple Leafs got hammered all season for having an unsustainable record, one built on shooting and save percentages that masked how badly they were outplayed. Where Calgary is statistically after 19 games isn't that far off. The Flames' PDO (combined shooting and save percentage) is sky high at 102.8; last year, the Leafs were at 102.6 when doomsday predictions were being made in part because of that number.

Both teams were very poor at controlling play, one telltale sign of an unsustainably good record.

Calgary has 24 points after 19 games. Toronto had 23.

The biggest concern for the Flames is going to be generating offence over the remaining 63 games. They lead the league in even-strength shooting percentage and are high on the power play as well, getting terrific contributions from captain Mark Giordano and a score-by-committee approach from the youngsters. There's a lot to like about the Flames' future right now. In addition to the kids playing well and producing, this is a hard-working group that has deserved better results in some areas such as the penalty kill. It's also possible Hiller – a huge off-season addition – has an outstanding season and keeps them in low-scoring games the rest of the way.

But almost every other indicator has them playing over their heads and ready for a fall.

Fans have to hope it's not nearly as gruesome as Toronto's 2-12-0 finish was a year ago.