They're battling Wednesday at Dallas's Toyota Stadium (7 p.m. PT) for the right to play Western Conference Supporters' Shield winner Seattle in the home-and-home conference semi-final that will begin Sunday in either Vancouver or Dallas.
During the regular season, fourth-place Dallas and the fifth-place Whitecaps, split their three meetings, 1-1-1.
Two of the matches featured confrontations with Dallas coach Oscar Pareja shoving Vancouver assistant Martin Pert in a heavily penalized match Oct. 4 as the Whitecaps won 2-0 in Vancouver. Sebastian Fernandez scored twice for the Whitecaps.
On Sept. 13, in a 2-1 Dallas FC triumph in Texas, Pert and Dallas assistant coach Josema Bazan were ejected.
The Whitecaps have not allowed any goals in October as they took 13 of 15 possible points, going 4-0-1 down the stretch to grab fifth place.
Their shutout streak has reached 393 minutes extending back to a Sept. 27 win against Salt Lake when they allowed a goal in the 57th minute in a 2-1 victory.
Dallas FC, on the other hand, had a chance to finish third in the Western Conference and avoid the one-game playoff, but lost their final match at home, 2-0 to Portland.
Vancouver hasn't had much luck at all in Dallas, losing all five trips to the Lone Star state, while being outscored 10-2. Overall, they're just 2-7-2 against Dallas FC.
It's the second playoff appearance for the Whitecaps, who lost a 2012 playoff to Los Angeles, 2-1.
Dallas is making its first playoff start in three seasons.