SEATTLE — The United States returned home from the FIFA Confederations Cup and used one of its youngest lineups in recent memory to rout Grenada 4-0 tonight as it opened the title defense in the regional championship of North and Central America and the Caribbean, the CONCACAF Gold Cup.

Freddy Adu scored the opening goal in the seventh minute and Stuart Holden doubled the lead in the 31st, both fed by Robbie Rogers.

Rogers scored in the 60th minute and Charlie Davies, one of the few players kept on from the Confederations Cup, got the final goal in the 68th.

The 12th-ranked Americans, seeking their third straight Gold Cup title, outshot No. 88 Grenada 25-3.

Seven of the U.S. starters entered with a combined 11 international appearances, with goalkeeper Troy Perkins playing just his second match for the national team.

Right back Steve Cherundolo, sidelined with a hip injury for most of the past six months, was the only regular starter in the lineup. He was joined by three frequent national team backups: left back Heath Pearce, and Adu and Davies, who got a key goal against Egypt at the Confederations Cup.

Adu's goal was just his second for the national team — the other was in a World Cup qualifier against Guatemala last November. Rogers. Holden, who turns 24 next month, became the first American to score in his international debut since Eddie Robinson against Sweden in January 2008, and Rogers scored his first goal in his second appearance. It was the third goal for Davies.

Most regulars were not included in the initial 23-man roster, allowing them to either take time off before the start of the European season or to return to their Major League Soccer teams. CONCACAF then decided to allow the U.S. to expand its roster by seven, and some regulars could be called in later in the tournament.

The U.S., 22-0-1 in group play in the Gold Cup, next plays Honduras on Wednesday in Washington, D.C., then closes the first round against Haiti on July 11 at Foxborough, Mass.

It was just the second time the U.S. soccer team has played on the Fourth of July — the other was a 1-0 loss to Brazil in the second round of the 1994 World Cup at Stanford, Calif.

The U.S. was coming off its first-ever final in the FIFA tournament, a 3-2 loss to Brazil last Sunday at Johannesburg in which the Americans failed to protect a 3-2 halftime lead.

Adu, who was on the Confederations Cup roster but didn't get into a match, scored the opening goal to excite the crowd of 15,387. Rogers sent a cross from the left, and Adu beat Desmond Noel from near the penalty spot.

Grenada, making its first Gold Cup appearance, had faced the U.S. just twice before, losing a pair of matches in 2004 during qualifying for the 2006 World Cup. It fell behind by two goals when Holden scored on a leaping header from 6 yards that went in off the bottom of the crossbar.

Rogers beat Noel from the top of the arc, and Davies slotted the ball in off a pass from Pearce.