The Whitecaps navigated the Rapids, pilfering the host side for a 1-0 away win.
Colorado held nearly 60 percent of possession and took 15 shots in total, six on target. However, an error from Drew Moor cost the host side the match.
Jordan Harvey was given the entire left flank free. Moor whiffed on his attempted clearance from Harvey's cross, and Mattocks pounced to tuck the loose ball past Matt Pickens.
That was Vancouver's only shot on goal, but it stood up as the winner.
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