TORONTO -- Are you nervous yet, Toronto FC fans?

Despite TFC coming off the best regular season in MLS history and steamrolling opponents along the way, there is very real cause for concern.

Toronto didn't just dominate en route to the Supporters' Shield this year. The team claimed the season's first league trophy on offer in record time, and by the biggest margin ever. TFC built up a whopping plus-37 goal differential on the back of a mind-boggling 74 goals scored and a stingy defence that was second-best in the league.

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By several metrics, the 2017 version of Toronto FC enjoyed the best season of any club since MLS was formed in the mid-90s.

And with MLS Cup being hosted in the friendly confines of BMO Field, where TFC has lost twice all year long, the final piece of an unprecedented domestic treble should be academic, shouldn't it?

Not so fast.

While the regular season was a thing of beauty for TFC and its fans, the postseason has been a different story. The high-flying Reds were replaced by a team that needed to scratch and claw its way back to the big dance, with a few heart-stopping close calls thrown in for good measure.

In short, TFC has not been the same side over the past two months that it was from March through October.

Perhaps that's not a bad thing, because the club went into MLS Cup in 2016 off the back of a historic playoff run that showed just how lethal the side can be when it mattered. Of course, it all came crashing to a halt when the Seattle Sounders figured out how to suffocate the high-octane attack that had come to define TFC in the games leading up to that blustery night at BMO Field.

With those experiences still fresh, perhaps Toronto's newfound pragmatic approach is just what is needed to get the battle-hardened side over the hump. This may be even more important against a Seattle club that knows how to get a result in a do-or-die game in TFC's home stadium.

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Regardless, the pressure is on Greg Vanney's side to perform. The raucous fan base, among the best on the continent in any sport, has come to expect excellence from its team in short order.

It's funny how much expectations can change, and how quickly. TFC was, just five years ago, called "the worst team in the world" by its then-leading striker, and throughout its first eight years of existence the Reds were known as the rich kids in the MLS class who had no idea how to properly spend their parents' considerable wealth.

Over the past three years, in the Tim Bezbatchenko-Greg Vanney era that steadily changed. The pieces were put in place for TFC to become the juggernaut its chequebook suggested it should be, and the 2016 MLS Cup near-miss coupled with this season's year-long dominance have made Toronto fans expect a cash-in.

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It's no longer acceptable to just be a contender. In 2017, TFC is the favourite, and anything short of Michael Bradley hoisting the Philip F. Anschutz Trophy on Saturday night will be deemed a failure by many.

Add in the fact that it's the Sounders on the other side of the field — the team that dared to go against the narrative of the burgeoning Canadian superclub by stealing the cup without so much as registering a single shot on goal during open play — and it's clear that there is no other option.

"The pressure is on them," Sounders head coach Brian Schmetzer told reporters this week. "There's no pressure on us. They're at home, they have the Supporters' Shield."

Schmetzer, who replaced Sigi Schmid at the helm of the Sounders midway through last season before overseeing an epic autumn run that culminated in Seattle's first-ever MLS Cup championship, knows about not being under pressure. His team was considered the underdog last year and, despite being the reigning champion and heading into Saturday in far better form than TFC, is once again the second choice for pundits.

And so Schmetzer is correct: The pressure is squarely on TFC's shoulders. To Toronto's credit, the team has dealt with everything thrown its way this year.

It hasn't been pretty of late, but it's been effective.