Sunday might be the day Portland wins the cup, or it might not be, but either way Sunday's result will not eliminate the Timbers. Here is a reminder of the current standings:
Portland Wins Sunday
If Portland wins Sunday they win the Cup as they will have 11 points and Seattle will be done with all their games and cannot earn any more points
If Portland Ties Sunday they win the cup as they will have earned 9 points and Seattle will have 7 with no games left. Vancouver is already eliminated from contention, so the last game in the competition will not affect the standings.
Seattle will then have 9 points but Portland still has a chance to win the cup depending on the result against Vancouver. If Seattle wins then the tiebreakers may determine the Cascadia Cup.
1.) Greater number of points earned in matches between the teams concerned
2.) Greater goal difference in matches between the teams concerned
3.) Greater number of goals scored in matches between the teams concerned
4.) Reapply first three criteria if two or more teams are still tied
5.) Greater goal difference in all cup matches
6.) Greater number of goals scored in all cup matches
7.) Smaller number of disciplinary points in all cup matches (yellow = 1 point, red = 2 points)
Seattle Wins Continued
With those in mind here are the Scenarios based on Seattle winning and by what margin they won by:
Seattle wins by any margin, Portland beats Vancouver
Portland will win the cup outright based on points as they would have 11 and Seattle would only have 9.
Seattle wins 1-0, Portland ties Vancouver
If Seattle wins 1-0 then Portland would need to earn 1 point against Vancouver to win the cup. If they earn one point Portland will be tied with Seattle at 9 points and the first tie breaker will not determine the winner as each team will have 4 points from the three games played against each other. The second tie breaker will not determine the winner as each team won by 1 goal and their tie would mean they each have a goal differential of 0. The third tie breaker would then determine the winner as Portland would have scored 4 goals in all games concerned and Seattle will have scored 3.
Seattle wins 2-0 (Or by more), Portland ties Vancouver
If Seattle wins 2-0 then Portland would need 1 point. Just as in the above scenario the first tie breaker would not break the tie but Portland would lose out on the second tie breaker as they would have a -1 GD and Seattle would have a +1 (Or more).
Seattle wins by 2-1, Portland ties Vancouver
If Seattle wins 2-1 and Portland ties then once again the first two tiebreakers will not be able to determine the cup winner. Neither will the third tiebreaker as Portland and Seattle will have scored 4 goals in the three games. It would then go to goal differential in all cup games and Seattle would win with a +2 GD compared to Portland's 0.
Seattle wins 3-2 (or more but loses by 1 goal), Portland ties Vancouver
As long as Seattle wins by 1 goal and scores more than 1 goal Portland will always lose on tiebreakers to Seattle if they tie Vancouver. Usually it would be the second or third tie breaker Portland would lose out on.
Best scenario for Portland
The best scenario for Portland would be to tie or win at Seattle. If they do this they will win the cup at C-Link without having to worry about the tie breakers. However if they lose at Seattle, they will need to win in their final game to leave no doubts they won the cup.