One of just two strikers currently part of Chelsea's tour roster, Lukaku muscled his way to a goal in the third minute of the international exhibition then scored his second goal in the final minute of the first half. It was the first match for Chelsea since the Blues beat Bayern Munich in May to win their first Champions League crown.
Seattle's Fredy Montero scored a pair of goals in the first half, but the Sounders missed a number of good scoring chances early and had few offensive opportunities in the second half.
Lukaku scored his first goal on a pass from Josh McEachran, one of the youngsters getting a chance to play for Chelsea coach Roberto Di Matteo while some Blues regulars are either resting from the European Championships or going to the Olympics. Lukaku forced his way past defender Jeff Parke to score his first then added another in the 44th minute as Seattle's defense continued to leak.
Chelsea's two biggest offseason signings - thus far - also scored in the first half with Hazard, coming over from Lille, scoring in the 11th minute after his shot deflected off defender Jhon Kennedy Hurtado and past goalkeeper Bryan Meredith. Marin, who picked up a pair of first-half assists, also scored in the 40th minute when his shot deflected off Parke.
Unlike last year's 7-0 rout at the hands of Manchester United, the Sounders made this match respectable and at times controlled the offensive chances. Alvaro Fernandez and Eddie Johnson both had missed headers off corner kicks and Fernandez's open shot in the 24th minute was punched wide by Henrique Hilario.
Montero's first goal came off a poor giveaway by McEachran in the back end. Montero patiently waited and beat Hilario in the 14th minute, the first goal scored by Seattle in any of its previous exhibitions against European powers Chelsea, FC Barcelona and Man United. Montero made it a pair in the 32nd minute when Mauro Rosales cross field pass fell to Montero's feet and his left-footed shot beat Hilario again.
Chelsea brought on regulars Frank Lampard, Michael Essien, Ramires and Gary Cahill at halftime and controlled more of the play but was unable to tack on additional goals.
The Blues were without five of their biggest names for the first stop of a four-game American tour that will feature the first soccer match at the new Yankee Stadium against Paris Saint-Germain, a match with the MLS All-Stars in Philadelphia and a final exhibition versus AC Milan in Miami.
Spanish star Fernando Torres, who helped Spain win the European Championship earlier this month, and Portugal's Raul Meireles will join the tour later. As will French midfielder Flourent Malouda and the English defensive duo of John Terry, just cleared of racial abuse charges last week, and Ashley Cole. Terry is expected to join Chelsea in New York this weekend.
Wednesday night was the final match for retiring Seattle midfielder Roger Levesque. The fan-favorite spent nine seasons with the USL-1 Sounders and the MLS Sounders and entered in the 66th minute to a standing ovation from the more than 53,000 in attendance.