Double amputee Oscar Pistorius still has a chance of winning an Olympic medal after South Africa were handed a place in the 4x400m final on appeal.
They looked as though they had blown their opportunity when team-mate Ofentse Mogawane fell in the heats.
But officials ruled that he had been blocked and decided South Africa should been given a place in Friday's final.
Pistorius, nicknamed "Blade Runner" because of his prosthetic legs, tweeted: "It's on!! We in the final."
Unfortunately for Mogawane, he will not run after suffering a shoulder injury in the collision with Vincent Kiilu of Kenya, who were disqualified as a result of the incident.
Originally, three teams from the two heats were supposed to advance automatically, along with the next two fastest times, but there will now be nine teams in Friday's final following South Africa's successful appeal.
Silver medallists at last year's World Championships, they will run in lane nine, with LJ van Zyl replacing Mogawane.
Pistorius, 25, was due to receive the baton from Magowane before the latter was sent sprawling.
The four-time Paralympic champion, who ran in the individual 400m at these Games, finishing eighth in his semi-final, had his legs amputated below the knee when he was a baby.
The Court of Arbitration for Sport cleared him to compete against able-bodied athletes in 2008.
Trinidad & Tobago, Great Britain, Cuba and Belgium qualified for Friday's final from heat one, with Bahamas, United States, Russia and Venezuela making it through from heat two.
Venezuela went through after a successful appeal against their disqualification for allegedly impeding Australia during a takeover.
Jamaica were a surprise casualty in heat two after Germaine Gonzales pulled up with a hamstring injury, ending any chance that Olympic 100m champion Usain Bolt might de drafted into their team for the final.