Two women who have made international headlines off the track made appearances in 800-meter qualifying Wednesday at the London Olympics.It was Caster Semenya's first, and Sarat Attar's first and only.

Attar, wearing a white headscarf, green long-sleeved shirt and black leggings, became the first Saudi woman to compete in Olympic athletics. With the 80,000-capacity crowd cheering, she finished her heat in 2 minutes, 44.95 seconds -- more than 40 seconds behind the fastest qualifier -- and failed to advance to the semifinals.

"It is the hugest honor to be here to represent the women of Saudi Arabia," Attar said. "It is an historic moment. I hope it will make a difference."

Semenya, making her Olympic debut three years after being forced to undergo gender tests, finished second in her 800 heat. The South African runner was sidelined for nearly a year while track and field's governing body, the IAAF, decided whether to allow her to compete after she won the 2009 world title at age 18. She was tested and eventually cleared to return to action in 2010, then was the runner-up at last year's world championships.

Semenya carried South Africa's flag at the opening ceremonies in London and is a leading medal podium chance in the 800.

"It was a tactical race, I wanted the race to be a fast one," Semenya said. "I have to run a sub-two (minutes) race to be a contender."

Earlier, a 36-year-old canoeist gave Norway its first gold medal of the games as China and the United States continued their intense games-long competition for top spot on the medal table.

Eirik Veras Larsen won the K-1 event over 1,000 meters at Dorney Lake west of London. Hungary won two of the four gold canoe and kayak medals decided there Wednesday -- Rudolf Dombi and Roland Kokeny had a photo-finish in the men's 1,000-meter K-2 and the Hungarian women's quartet ended the 16-year dominance of their German rivals in the K-4 500.

China took over top spot in the gold medal race last weekend after the U.S. had led for most of the first week. China had 34, the U.S. 30 and Britain 22 early Wednesday with more than 200 of the 302 medal events completed in the games that end Sunday.

On Wednesday, China was a near-certainty to pick up another gold in the men's team event in table tennis, where they've won every gold on offer so far. The Chinese could also pick up a gold in taekwondo, where Jingyu Wu was one of the favorites in the women's 49-kilogram class.

But the Americans will cut into the Chinese lead in the women's final in beach volleyball -- Kerri Walsh Jennings and Misty May-Treanor, who are aiming for their third straight golds, play the younger American pair of April Ross and Jennifer Kessy in the final at Horse Guards Parade.

"We want to seal the deal that we're the best team that's ever happened," Walsh Jennings said after the two-time gold medalists advanced to their third Olympic final by beating China in straight sets. "I want to win tomorrow for us. ... This will be our last match together, so we want to go out on top."

The U.S. is also favored in several track events and Brittney Reese is a strong gold medal chance in the women's long jump.

And Rich Fellers is among the leaders going into the final round of show jumping at the equestrian complex at Greenwich Park.

In evening finals at the Olympic track, Veronica Campbell-Brown will attempt to succeed where Yelena Isinbayeva failed.

The Jamaican sprinter runs in the 200-meter final in a bid to become the first woman to win the same track and field event at three consecutive Olympics. Isinbayeva fell short in her attempt when she could only manage bronze in the pole vault on Monday.

"I'm not focusing on (history). The objective is to make sure that I navigate my race good tomorrow," the woman known as "VCB" said. "It's going to be very competitive. I have to stay focused and make sure I make no mistakes."

Among those trying to stop Campbell-Brown's run into the history books will be fellow Jamaican Shelly-Ann Fraser-Pryce, who already has won the 100-meter gold and could complete the coveted sprint double.

In the men's 200, their countryman, Usain Bolt, will run in the semifinals as he continues his quest to defend the title he won in Beijing and add to the 100-meter gold he already won in London.