So watched a bit of the game. RSL was gifted two goals by the Timbers (the 2nd and 4th). Given that, they were still duly outplayed and their pressing game had little impact on RSL.
The tie at home will come down to what adjustments Porter makes to his approach, and whether RSL changes anything. I dont really by into "home field" advantages as much as I do system matchups, and at the moment Portlands strengths are countered by RSL. Not even a chain saw wielding fan is going to change that.
I believe Porter will run at RSL and try and force early mistakes. this will leave his group open in the back. if they make mistakes (as Seattle did in the 2nd match) it will get away from them. if RSL break the press and find their midfield it will get away from them.
Not over by a stretch, but long is the imagination that sees a Timber win.