LONDON -- The U.S. Olympic men’s basketball team led Argentina by just one point at halftime, and American fans watching on TV back home surely were getting nervous, especially after the near-upset by Lithuania over the weekend and Argentina’s history of upsetting the Americans in big games.

Enter LeBron James.

U.S. coach Mike Krzyzewski told the Heat star just after halftime that the team was going to him in the paint to start the third quarter. For the second game in a row, James responded to the challenge and came through when it mattered most.

He scored the first seven U.S. points of the second half and was a big reason the Americans turned that one-point game into a 126-97 blowout to clinch their group and advance to Wednesday’s quarterfinal against Australia.

James swung the game’s momentum, and Kevin Durant then caught fire from three-point range, making 5 of 6 three-point attempts in the third quarter. The United States outscored Argentina 42-17 that quarter and never looked back in a game that got more physical as the second half wore on. Durant finished with 28 points and was 8 of 10 from beyond the arc. James added 18 and had five assists.

“LeBron did a great job of starting the third quarter, bringing energy, and we kind of fed off of him and I was able to make some shots,” Durant said.

Said James: “Kevin and I took it upon ourselves to take over the third quarter. When it’s a close game you’ve got to go down and get some easy shots. They were carving us up. I wanted to come out in the second half with a greater sense of urgency. We’ve got to play like that a little closer to 40 minutes, not 20.”

James had been criticized for deferring to others when games were on the line, but here at the mattress-shaped Olympic Park basketball arena, he has taken charge and been a leader.

“LeBron is special, what more can you say?” said U.S. guard Chris Paul, who scored 17 points. “We came to the bench and I heard Coach K tell him, ‘Take the game over.’ He’s the guy that’s capable of doing that. A lot of times when you think about guys taking games over, you think about scoring. But he’s the guy that can take the ball over on the defensive end. He got a huge offensive rebound at a key moment and went from there.”

No matter which medal the United States takes home, James surely has already won some goodwill with fans back home. He certainly has earned a lot of respect from his U.S. coaching staff and teammates.

“We needed to pick it up a little bit more, and I wanted offensively to start the second half going to him, in the post, which is where we usually don’t go, and he responded right away,” Krzyzewski said. “LeBron has been kind of our quarterback on defense, with his voice. He was all over the place defensively, especially in third quarter. His play on defensive end was magnificent.”

Asked why he chose to go to James, Krzyzewski smiled and replied: “I watched his workout [Sunday] at practice. It was pretty good.”

James was instrumental in the 99-94 win over Lithuania as well. He scored nine of his 20 points in the final four minutes of that game, helping the United States avert a potentially embarrassing loss.

It looked for a while like this one might also go down to the wire. Argentina was shooting 56 percent at halftime and humbling the NBA superstars, which should not have come as a big surprise to anybody who has been following international basketball over the past decade.

In Indianapolis 10 years ago, Argentina’s “Golden Generation” team knocked off the United States in the world championships. Two years later, the Argentines beat the Americans again in the semifinals of the 2004 Athens Olympics on their way to the gold medal. The United States settled for bronze. A few weeks ago, they had another close — and heated — battle in an exhibition game in Barcelona.

Things Monday night got “a bit chippy,” in the words of a British journalist who asked Krzyzewski about Carmelo Anthony being hit in the groin by Facundo Campazzo as Anthony took a three-point shot late in the third quarter. Players exchanged words and technical fouls were called.

“It was more than a tap,” Anthony said, laughing. “I’m fine. I’m cool. He did what he did. You come down in transition and you’re wide open and for somebody to do that, it was a cheap shot.”

Kobe Bryant confronted Campazzo about the foul.

“It was very inappropriate,” Bryant said. “I said ‘You know you don’t do that.’ ”