SEATTLE (Reuters) - The United States made a winning start to their defense of the CONCACAF Gold Cup on Saturday with a comfortable 4-0 victory over Grenada while Group B rivals Honduras beat Haiti 1-0.

The U.S, featuring a different lineup to the one that reached the final of the Confederations Cup last month, took the lead in the eighth minute when Freddy Adu calmly slotted home after good work from Robbie Rogers.

The impressive Rogers had a hand in the second goal, crossing for debutant Stuart Holden to head home and then added the third himself after the break with a cool finish.

Grenada, playing in their first major international competition, struggled to cope with the artificial surface at Qwest Field, with several players struggling with cramp in the latter stages.

U.S. striker Charlie Davies completed a confident display from Bob Bradley's team, with a clinical shot after a superb set-up from Heath Pearce.

In the earlier game, Carlo Costly headed home the winner for Honduras in the 76th minute against Haiti. Honduras play the U.S. in Washington D.C. on Wednesday.

(Editing by Greg Stutchbury)