LONDON — China is back in command at the Olympic diving pool.

He Chong took the lead in the men’s 3-meter springboard semifinals Tuesday to put his country in position for its sixth diving gold medal of the London Games.

He totaled 510.15 points during the six rounds after starting the semifinals in second place behind Ilya Zakharov of Russia.

“My performance is just so-so,” He said. “I still have room to improve for the final because I can do much better in training. I especially hope I can have less splash.”

Zakharov fell to ninth midway through the round and rallied to finish second at 505.60.

He’s teammate, Qin Kai, was third at 500.35.

“I was upset because I slipped during the preliminary, so I only wanted to make it into the final,” Qin said.

Yahel Castillo of Mexico was fourth and four-time Olympian Troy Dumais of the U.S. was fifth. The top 12 advanced to the evening final, where China will try to win its sixth diving gold and move closer to sweeping all eight events.

In other action:

Alex Morgan’s looping header gave the U.S. women’s soccer team a dramatic 4-3 overtime victory against Canada on Monday night.

And this physical classic was only the semifinal.

Morgan put the U.S. in front for the first time in the third minute of injury time at Old Trafford. Megan Rapinoe scored in the 54th and 70th minutes, and Abby Wambach in the 80th on a penalty for the U.S.

Morgan’s 6-yard header, on a long cross from Heather O’Reilly, went high into the net over goalkeeper Erin McLeod for the winning score.

The Americans overcame a hat trick from Christine Sinclair, who scored in the 22nd, 67th and 73rd minutes for Canada.

Next comes the game the U.S. players have been eyeing for more than a year, a rematch with Japan on Thursday at Wembley Stadium with gold on the line. The top-ranked Americans lost to Japan on penalty kicks in the World Cup final last summer.

In men’s basketball, Kevin Durant helped the U.S. team put away Argentina with one impressive shooting burst.

Durant scored 17 of his 28 points during the Americans’ 42-point third quarter, turning a one-point game into a blowout that sent the U.S. soaring into the quarterfinals with a 126-97 victory over Argentina.

Carmelo Anthony made a 3-pointer in the final second of the big third while taking what he and the U.S. bench right behind him felt was a cheap shot from Argentina’s Facundo Campazzo, setting off an exchange of words and technical fouls.

The Americans (5-0) will play Australia (3-2) in a quarterfinal game Wednesday.

Also Monday, American judo fighter Nick Delpopolo apologized after he was expelled from the Olympics for doping, blaming the disqualification on his unintentional consumption of something baked with marijuana.

Delpopolo is the first of the 10,500 London Games athletes to fail an in-competition doping test.

The International Olympic Committee said it disqualified him from the 73-kilogram class, where he placed seventh.

Defending Olympic 50K race walk champion Alex Schwazer also tested positive for doping, and the Italian Olympic Committee said he had been removed from the team. Schwazer was scheduled to compete on Saturday.

Jenn Suhr has been America’s best female pole vaulter for a while. Now she’s the best in the world.

Suhr rounded out her resume with Olympic gold, vaulting 15 feet, 7 inches to defeat Cuba’s Yarisley Silva, who cleared the same height but lost on a tiebreaker because she had one more miss in the competition.

Grenada’s Kirani James won the men’s 400 meters and 35-year-old Felix Sanchez of the Dominican Republic took the men’s 400-meter hurdles on a rainy night at Olympic Stadium. Other track and field winners included Belarus’ Nadzeya Ostapchuk (women’s shot put) and Russia’s Yuliya Zaripova (women’s 3,000-meter steeplechase).

Michael Tinsley was second in the 400 hurdles, but it was a disappointing session for the U.S. overall. The U.S. was without a representative in the 400 final.

and it was the first time since the 1980 Moscow Games that someone other than an American won the race.

In gymnastics, Gabby Douglas was nowhere near the podium this time. The all-around champion, who also helped the United States to team gold, finished last on uneven bars. Russia’s Aliya Mustafina rallied to the victory.

“Toward the end of the Olympics, you get mentally and physically tired and you’re just like drained,” Douglas said. “I tried to fight through it as much as I could.”