The Sounders Designated Player created both goals as he added assists to his bag of tricks which has so far yielded six goals in 13 MLS appearances.
Martins played a superb through ball for Brad Evans to score the 23rd minute leveller - following Erick Torres' 16th minute opener for Chivas - before setting up Mauro Rosales who played in Lamar Neagle for the eventual winner just before the hour-mark.
"It was a good battle of possession, some good passing and Oba found me slipping through the middle," Evans said. "First time shot and luckily beat Kennedy."
Neagle added: "Yeah, we've played together for a little while and we kind of know each other's tendencies now. A couple of passes went astray but that's always going to happen when we're trying to pressure and get in behind."