Vancouver Whitecaps & Seattle Sounders square off on Twitter | SIDELINE

Oh, those Cascadia Cup clubs. They're at it again. 

After the Seattle Sounders beat the Colorado Rapids in the Western Conference Knockout Round game and booked a date with the Portland Timbers in the Conference Semifinals, the Vancouver Whitecaps – who won this year's Cascadia Cup but missed the playoffs – jumped onto Twitter to trash-talk both of their rivals.

Here's how it went down (start reading from the bottom).

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