Belgian teenager Romelu Lukaku led the line impressively at CenturyLink Field, opening the scoring in the third minute after being put through by Josh McEachran and grabbing another two minutes before half-time.
Hazard’s deflected effort in the 10th minute put the European champions two goals up, before Fredy Montero’s brace – the first of which came following a misplaced McEachran pass – got the Sounders back on level terms.
However, Marin marked his debut with a fine strike to put Roberto di Matteo’s side ahead again in the 39th minute and Lukaku rounded off an entertaining first half with a fourth goal four minutes later.
Di Matteo made seven changes at the interval, including the introduction of Kevin De Bruyne, but there were no further goals.
Chelsea now head to New York to face Paris Saint-Germain – coached by former Blues boss Carlo Ancelotti – on Sunday in what will be the first football match at the new Yankee Stadium.