United thrashed Seattle 7-0.
Sounders keeper Keller told the Seattle Times: "Have you ever heard the cliche, 'A game of two halves?' It was kind of that a little bit. Hopefully it's a learning experience. We put so many guys out on the field in the second half [...] because everybody thinks they can play in the Premier League in America.
"Everybody thinks, 'Oh, if I just got the break that I could be there.' And actually, no you can't and you need to learn to figure that out. I was talking to Sir Alex afterwards, walking off the field, and they're one of the best counter-attacking teams in the world and we gave them all the space in the world to do exactly what they're best at. You have to learn. You have to adapt. You have to figure out how things are going in the game and make it right.
"The second half was extremely disappointing. But he [Sir Alex] was very gracious, he said, 'The score line wasn't indicative of the result.' So that's a little comfort. We had great chances. We know their keepers made some good saves, but we needed to be that [...] I mean you saw how clinical Wayne Rooney is in the box. You give him that chance and he's going to bury it and they did exactly that."