Caster Semenya retained her 800-meter title at the South African championships on Saturday, while double-amputee sprinter Oscar Pistorius finished seventh in the 400 final.

The world silver medallist led the two-lap final almost from start to finish but could only manage 2 minutes, 2.68 seconds with no one to push her below the 1:59.90 she needs to be eligible for South Africa's team in London.

"It was OK for me because I retained my title, that's what's important," Semenya said. "It was disappointing because we were hoping for a qualifier ( time) and unfortunately we didn't make it. But the time will come. We just need to be patient."

Pistorius finished the 400 final in 47.28, backing off in the last 50 meters after he struggled to recover from a slow start despite running in lane two.

Lebogang Moeng won in 45.75, but Pistorius is still the only men's 400 runner in South Africa to post an Olympic qualifying time this year after his season-opening 45.20 last month.

He needs one more run below 45.30 seconds on his carbon fiber blades in an overseas event to be eligible to go to London.

Semenya eased home in the south coast city of Port Elizabeth for her second straight national title, but hasn't gone under two minutes this year. She has yet to shake off a sluggish start to her Olympic preparations under new coach Maria Mutola.

Mutola, the former Olympic 800 champion, had targeted the nationals for Semenya's first sub 2-minute run of 2012.

"I don't feel pressure (to qualify). I just need to do my thing," Semenya said. "I train hard, I know what I need to do, so I don't need to stress. I know I can do it. The Olympics is a big step, man, everyone wants to win the Olympics. And so do I."

Semenya also ran in the 4x400 relay at the end of Saturday's meet, helping provincial team Gauteng North to victory.

The 21-year-old Semenya, whose career was interrupted for 11 months following gender tests in 2009, needs one more time of 1:59.90 or better to qualify for her first Olympics. She has until the Olympic qualifying cutoff of June 30.

It was just her second 800 race of the season. But she was still off the 1:55.45 she ran to win the worlds in her stunning international debut three years ago. She claimed silver at the 2011 worlds in 1:56.35.

Pistorius smiled and waved to fans as he left the track, seemingly unconcerned with his seventh place. He also said he would appear in the 400 relay to finish the two-day nationals.

Earlier, world championships bronze medallist L.J. van Zyl lost his national title to rival Cornel Fredericks in the 400 hurdles. Fredericks won in 48.91 seconds to qualify for the London Games, with Van Zyl second in 51.00. Van Zyl has already qualified for the Olympics.

"It wasn't my best race," Van Zyl told The Associated Press. "I've got a few niggles that's bothering me. Nothing serious, I'll be back. The most important thing for me is to stay injury-free and to stay focused."

Mbulaeni Mulaudzi won the men's 800 final in 1:45.78 to just miss the Olympic qualifying mark by 0.18 seconds.

Sunette Viljoen, who claimed bronze at last year's worlds in Daegu, South Korea, won the women's javelin title. That means she met the qualifying criteria for the Olympics, which start July 27.

Most of South Africa's top athletes were in Port Elizabeth after the country's track and field body ruled that appearing at the nationals was a requirement to be eligible for the Olympics.


Follow Gerald Imray at: http://twitter.com/GeraldImrayAP