Suwon, South Korea ? What a way to start a World Cup.

Branded last-place losers for four years, the United States gave soccer – and the folks back home – a wakeup call Wednesday with a shocking 3-2 upset of Portugal, the world’s fifth-ranked team.

“I think this victory will grab the attention of a lot of people in the United States,” U.S. coach Bruce Arena said.

Missing Claudio Reyna, their best player, and Clint Mathis, their most imaginative attacker, the Americans took a 3-0 lead in the first 36 minutes behind goals by John O’Brien and Brian McBride, and a cross by Landon Donovan that a Portuguese defender knocked into his own net.

The U.S. players looked stunned by their success.

“I think Portugal was the same way,” said O’Brien, one of six American starters to make their World Cup debuts.

O’Brien scored in the fourth minute, the deflection of Donovan’s pass went in in the 29th and McBride connected on a beautiful diving header in the 36th. The United States had taken its first three-goal lead in a World Cup game in 72 years.

“It seemed like there was a little mist, a weird stadium and colorful seats,” O’Brien said. “It was a weird night.”

Arena went for brash youth with speed, inserting a pair of 20-year-olds, Donovan and DaMarcus Beasley, to neutralize a fast team known for its repeated attacks.

The U.S. defense, maligned as it went 0-4 against European opponents in World Cup warmups, held under intense pressure from Portugal in the final 10 minutes of the first half and the first 40 minutes of the second, withstanding Luis Figo, the world’s top player, and his talented teammates.

The result was among the five greatest wins in U.S. soccer history: 3-0 wins over Belgium and Paraguay at the 1930 World Cup, the 1-0 upset of England at the 1950 tournament and the 2-1 win over Colombia at the Rose Bowl in 1994, when the United States was host of soccer’s showcase event.

“The two 20-year-olds played with the best of the world and did very well. They were terrific,” said Robert Contiguglia, the U.S. Soccer Federation president.

With Wednesday’s win, they head into their remaining first-round games against co-host South Korea and Poland with a good chance to advance. The South Koreans opened Tuesday with a 2-0 upset of Poland.

“This World Cup is not over,” Arena said. “We’ve got to prepare for Korea, and our goal is to win that game.”

With a youthful lineup – and without their two most creative players, injured Claudio Reyna and Clint Mathis – the Americans jumped ahead 3-0 within 36 minutes, then held on at Suwon, South Korea.

“We took advantage of our chances,” said Brian McBride, who scored the winner. “We bunkered in and held them off.”

John O’Brien, one of six U.S. players making their World Cup debuts, scored just four minutes in. The Americans got another in the 29th minute when a shot by Landon Donovan, one of the two 20-year-olds in the lineup, deflected in off a defender.

McBride’s header gave the U.S. team its first three-goal lead in a World Cup in 72 years.

Back came Portugal, ranked fifth in the world, but making its first World Cup appearances in 16 years. Beto scored off a scramble in the 39th. U.S. veteran Jeff Agoos, making his World Cup debut at age 34, tried to clear a cross by Pauleta with his left leg, only to send the ball into his own goal in the 71st.

But the Americans, in the most pressurized situation they’ve faced, held on.

“It was important to come out quickly,” McBride said. “They’re a very good team, we needed to make sure we put them on their heels early. In the second half we probably sat back a little bit.”

Now they can look ahead to a match with co-host South Korea, which beat Poland on Tuesday. The winner of that game – can you believe it? – will clinch a spot in the next round.