Sunday night's first leg of the Western Conference semifinals between the Vancouver Whitecaps and Seattle Sounders may be the clubs' first ever MLS postseason meeting. But their clash in the 2017 Audi MLS Cup Playoffs is just the latest chapter in one of the longest rivalries in North American club soccer history.
The match Sunday (8:30 pm ET | ESPN, TSN 1/4, TVAS 2) will be the 144th encounter between the two clubs going all the way back to an NASL rivalry that began in 1974.
Their first NASL playoff match came two seasons later, when the Sounders emerged as 1-0 victors in a winner-takes-all first round match. But the Vancouver Whitecaps would become the only side from the Pacific Northwest to win an NASL Championship in 1979.
The demise of the NASL brought a hiatus to rivalry matches played between the two cities, one that ended when both fielded sides in the APSL in the 1990s. That league later morphed into the A-League and then the USL 1st Division.
With Seattle coming into MLS in 2009 and Vancouver following in 2011, the rivalry was renewed in a true North American first division. The old foes also met twice during group play of the 2015-16 CONCACAF Champions League, with Seattle earning four points out of six to advance from the group.
