The Argentine-Armenian playmaker, who arrived from Tigres in the offseason in a deal worth a reported $7 million, opened the scoring in the 25th minute when he fired a low-volley past Seattle keeper Stefan Frei.
The 28-year-old turned provider for the second goal, finding Derrick Etienne Jr. in space, with the Haitian winger unleashing a curling effort past Frei into the far corner.
Zelarayan netted his second in the 82nd minute after neat wing play from Luis Diaz to become the second player in MLS Cup history to be involved in three goals in a final after the Crew’s Guillermo Barros Schelotto in 2008.
Crew coach Caleb Porter described Zelarayan as “unbelievably special”.
“I’ve coached good players before but this guy is unbelievable.
“We shared a great moment after the game. He told me I changed his life. And I told him he changed my life.
“I brought him here to win championships. He seemed to be looking for something new to stimulate him. A lot of time I’ve seen guys are cutthroat, they sell their souls a little and lose their way. But he came here and I think he looks like a new man.” Porter said of Zelarayan.
Born in Córdoba, Argentina, Zelarayán is of Armenian descent. He received an invitation to represent the Armenia national team in June 2018.