The Seattle Sounders pulled off a remarkable 3-1 win over Toronto FC to win their second MLS Cup at a jam-packed CenturyLink Field on Sunday afternoon.

It was the third meeting in four years for the two teams in the MLS showpiece, with Seattle having won the Cup in 2016 and Toronto taking it home in 2017.

Toronto was the better of the two sides in a lacklustre first half, but had nothing to show for it, while Seattle missed a chance to take the lead right before half-time only for Raul Ruidiaz to shoot tamely at Stefan Frei.

The hosts took the lead right before the hour mark when Kelvin Leerdam's shot from the right side of the penalty area took a wicked double deflection and left Quentin Westberg no chance in the Toronto goal.

It was the first time that Seattle was able to score on Toronto during the run of play in 267 minutes of MLS Cup play between the two.

Greg Vanney brought on Jozy Altidore in search of an equalizer, but it was Seattle substitute Victor Rodriguez who struck instead, picking up a nice pass from Nicolas Lodeiro, cutting to his right and firing a low, knuckling shot past Westberg to double the Sounders' lead.

And Ruidiaz added a third for Brian Schmetzer's team after outrunning his marker and curling a shot around Westberg, before Altidore netted a meaningless consolation goal for Toronto in stoppage time.

The crowd of nearly 70,000 represents the largest non-concert attendance at any event in the history of CenturyLink Field, which hosts the NFL's Seattle Seahawks.