South African double amputee Oscar Pistorius says he is stunned to have shattered his 400m personal best.
Pistorius ran 45.07 seconds to improve his best time by nearly half a second and post the Olympic qualifying time.
He told Radio 5 live: "I'm taking a bit of time to let it all sink in. It seems very surreal.
"To better a personal best by half a second is pretty much unheard of in a whole season, but to do it in one race is just a dream come true."
The 24-year-old double amputee will now compete in next month's World Championships in South Korea.
After beating his previous personal best of 45.61 seconds, Pistorius said he felt "weird" but promised to keep improving in order to stand a chance of winning a medal at the highest level.
On his chances of winning a medal at the London Olympics in 2012, Pistorius said: "I think it's one thing running the time I did last night, but it's another thing doing that consistently.
"In a championships when you've got five races leading up to a final, these guys are able to run these races every day. It's still going to be a huge challenge.
"I think I'm ranked 14th in the world at the moment with my current time. So if I make the final I will be extremely happy."
Pistorius will become the first amputee runner to compete at an able-bodied World Championships, and has taken a big step towards being selected for the London Games.
He needs to run the 'A' standard time of 45.25 seconds twice next season to meet the selection criteria of the South African Olympic Committee.
However, Pistorius is in no mood to take it easy now, saying: "I'd like to run a couple more 'A' times before the Worlds."
His next chance to do that will be in Budapest on 31 July - he also hopes to run at the Diamond League event at Crystal Palace on 5-6 August.
He took to Twitter to thank his supporters, saying: "This morning feels insane. I'm really overwhelmed by all the support, thank you all for the messages. Hard work definitely pays off."
The chairman of Athletics South Africa, James Evans, said: "Now he knows he can do it, there's no reason why he can't keep on doing it.
"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."
A congenital condition meant Pistorius was born without fibulae - lower leg bones - and led to the decision to amputate both legs below the knee when he was 11 months old.
He preferred rugby union, water polo and tennis as a schoolboy and only took up running seriously in 2004 after being prescribed it as part of his rehabilitation from a rugby injury.