Clint Dempsey celebrates the first of his three goals Saturday in a 6-0 U.S. win over Cuba in the CONCACAF Gold Cup quarterfinals at Baltimore’s M&T Bank Stadium. (Patrick Semansky/Associated Press)

The outcome was settled well before halftime, a breezy victory on a roasting summer day in Charm City. The U.S. men’s national soccer team made quick work of a Cuban squad undercut by political defections, 6-0, in a CONCACAF Gold Cup quarterfinal before 37,994 at M&T Bank Stadium.

Clint Dempsey headed in the fourth minute, and Gyasi Zardes volleyed in the 15th. Aron Johannsson chipped in the 32nd minute, and Omar Gonzalez swept in the 45th.

Dempsey added two goals in the second half to notch his first international hat trick and increase his tournament-best tally to six and U.S. career mark to 47 — 10 behind the retired Landon Donovan in the American record books.

“We wanted them to take it really seriously,” Coach Jurgen Klinsmann said of his players’ mind-set. “We didn’t want to waste anything. We didn’t want to fool around or show off. I made it very, very clear: If someone on the field takes it lightly, I am going to take them off after 10 minutes.”

No changes were necessary. The Americans were merciless and clinical, parading to Wednesday’s semifinal in Atlanta against Jamaica, which defeated Haiti, 1-0, in the second semifinal in Baltimore.

The other bracket will be settled Sunday at MetLife Stadium in East Rutherford, N.J., with Trinidad and Tobago against Panama and Mexico vs. Costa Rica.

While Klinsmann’s lineup decisions created mild intrigue, political defections left the Cuban roster in peril. Four players were known to have left the delegation in the past 10 days; five names were crossed off the official list before kickoff, leaving the team with 18 players.

Univision reported that, following a 1-0 victory over Guatemala on Wednesday in Charlotte, attacker Ariel Martinez, 29, was in tears as he ran from the team bus upon returning to the hotel.

“The players that aren’t here now don’t really mean anything to us because they have chosen their path,” Cuba Coach Raul Gonzalez said through an interpreter.

On Friday, Klinsmann spoke of how the off-field turmoil could galvanize the overmatched Cubans. He emphasized the importance of setting the terms right away and pressing for an early goal.

He had to wait just 3 1 /2 minutes.

Zardes tracked down Fabian Johnson’s cross on the far side of the penalty area and touched the ball back to Timmy Chandler for a high ball from 30 yards that met Dempsey for an eight-yard header over goalkeeper Diosvelis Guerra.

Eleven minutes passed before Johnson swung a left-side cross to Zardes, a 23-year-old Los Angeles Galaxy attacker, for an almost effortless six-yard volley and his second career goal.

“Just to get the first two goals is wonderful because that team just kept chasing the ball,” Zardes said, “and we tried to keep it as much as possible just to drain them.”

Both teams had to contend with a game-time temperature of 91.5 degrees and thick humidity, but with a two-goal deficit, the Cubans wilted first. They posed no threat, desperate just to avoid embarrassment.

The Americans scored twice more before halftime.

Michael Bradley’s 50-yard ball over the top of the Cuban defense linked with Johannsson. He settled it, then chipped Guerra from the top of the penalty area for his fourth international tally.

The fourth strike came just before intermission: a corner kick by Bradley, a header by Johannsson and a four-yard finish by Gonzalez, the former Maryland Terrapin who recorded his first U.S. goal in 28 appearances.

Given the lopsided score, Dempsey’s 64th-minute penalty kick did not elicit the usual celebration. He had, however, taken a cheeky approach, sending a soft shot down the middle as Guerra covered the left corner.

In the 78th, Bradley’s diagonal ball inside the penalty area found Dempsey for an angled, sliding, side-footed finish.

The Seattle Sounders star had enjoyed four two-goal games in his 101/2-year national team career but never a hat trick until Saturday.

“It took him a long time,” Klinsmann joked afterward.

With little fanfare after the last goal, Dempsey accepted a hug and handshake from Bradley. Atlanta awaited.

“That confidence definitely grows in the team,” Dempsey said. “And as the tournament goes on, we are getting stronger as a group, and hopefully our best ball is yet to come.”

In the second match, Giles Barnes (Houston Dynamo) scored from a tight angle in the seventh minute as Jamaica secured its first semifinal berth since 1998.

Notes: Midfielder Kyle Beckerman, an Anne Arundel County native, played the first 45 minutes. . . .

Chandler left at halftime with a sore knee. DaMarcus Beasley, who came out of international retirement this week to join the Gold Cup squad, was held out with a calf ailment. . . .

Gonzalez started in place of John Brooks, who served a yellow card suspension.