JOHANNESBURG, South Africa - Double-amputee sprinter Oscar Pistorius achieved a career goal by qualifying for the world track championships, fulfilling a five-year-long quest to compete at the highest level against able-bodied athletes.

Now he plans to train harder and run faster.

A day after smashing his personal best in the 400 metres to qualify for worlds next month, the 24-year-old runner told The Associated Press that the weight on his shoulders had been lifted.

"I feel amazing. The pressure has been released," Pistorius said Wednesday in a phone interview. "I was confident, but never in my life did I think I would beat my personal best by such a big margin."

He qualified with a personal best in the 400 at a meet Tuesday night in Lignano, Italy. He clocked 45.07 seconds in his final race before the qualifying cutoff. His previous best was 45.61, but his sensational performance was well inside the 45.25 qualifying time.

Pistorius said his achievement still felt "weird" and "surreal" and hadn't sunk in yet.

"It was my last chance, but I was quite confident," he said. "It's a goal for me, a dream come true."

Pistorius is set to be the first amputee runner to compete at an able-bodied world championships, which start Aug. 27 in Daegu, South Korea. The South Africa track and field association said Pistorius is "qualified for selection" and only can be bumped from the team if three South African runners post a better time before the approaching qualifying cutoff date.

He's also taken a big step toward competing at the 2012 Olympics. However, Pistorius needs to run the "A" standard twice next season before the London Games to meet the South African Olympic Committee's automatic selection criteria. Yet his time Tuesday was a major breakthrough.

Less than 24 hours after his "highest career moment," the man nicknamed "Blade Runner" was already on his way to his training camp in Gemona, in northern Italy.

"I'd like to run a couple more 'A' times before the worlds," Pistorius said while travelling by car from Lignano to his Italian base. "It's been 18 months (to) two years of hard work to get here but you have to keep training, keep working. I'm very excited."

Pistorius' road to the worlds and possibly the Olympics included fighting a ban by the International Association of Athletics Federations after it ruled his carbon-fiber blades gave him an unfair advantage. Pistorius took his case to the Court of Arbitration for Sport and won the right to compete against able-bodied athletes in 2008.

However, he didn't come close to qualifying for the 2008 Beijing Olympics. Pistorius' agent, Peet van Zyl, said he used that legal struggle to inspire the runner to one final effort in Lignano.

"I spoke to him before the race and told him 'Listen, this is what it's all about. This is what we fought the court cases for," Van Zyl told the AP.

Pistorius says the court challenge is in the past.

"It was so long ago, I've put it behind me," Pistorius said. "I don't think about it anymore."

Running the qualifying time was easily his best moment, he said, in a seven-year career that began after he was advised to take up running to rehabilitate a rugby injury. Pistorius had his legs amputated below the knee when he was 11 months old because he was born without shin bones.

He's the world record-holder in the 100, 200 and 400 for disabled athletes, and a multiple gold medal winner at the Paralympics. His goal has been to run against able-bodied athletes at the Olympics.

It seemed unlikely after he missed out on the qualifying time at meets in the Czech Republic, France and Diamond League events this season in New York and Eugene, Ore. Over the weekend, Pistorius struggled to a time of 46.65 in Padua, Italy. Yet he came through with his best run on Tuesday night.

He will run July 31 at a meet in Budapest, Hungary, and hopes to compete at the Diamond League event at Crystal Palace in London on Aug. 5-6. That's where he's looking to run another "A" time in preparation for his world championships debut.

Pistorius will be back competing in the British capital next year -- and may realize his Olympic dream -- if he can maintain the form he showed in Lignano.

There will be no special treatment for Pistorius, South Africa's Olympic committee and track federation said. He will have to achieve the qualifying standards next year.

"Now he knows he can do it, there's no reason why he can't keep on doing it," Athletics South Africa chairman James Evans said. "The way we've treated Oscar has always been we are not going to do him any favours, and we are not going to hold anything against him.

"He will be treated like any other athlete."