In 2008, 11.17 seconds earned him Paralympics gold. In 2012, it was merely good enough for fourth place.
Great Britain's Jonnie Peacock won one of the showcase races of the Paralympics in a speedy 10.90 seconds, outclassing U.S. sprinter Richard Browne (11.03 seconds) and South Africa's Arnu Fourie (11.08). Pistorius has now failed to defend two of his Paralympics titles from Beijing, having already finished second in the 200 meters Sunday.
That Pistorius came up short in the 100 meters is a testament to the progress Paralympic sprinters have made the past four years. Whereas Pistorius swept all three individual sprints in Beijing, other competitors have since improved to the point where they can challenge him and even beat him in his weaker events.
Pistorius, known as "Blade Runner" because of his two carbon fiber prosthetic legs, often falls behind at the start of races because his springy blades force him to pop straight up out of the blocks rather than driving out low and reducing wind resistance. A long sprint like his trademark 400 meters provides him ample time to recover from an early deficit, but the start is much more crucial in the 100.
Give Pistorius credit for accepting defeat with far more grace Thursday than he did four days earlier after placing second to Brazil's Alan Fonteles Cardoso Oliveira in the 200.
"We aren't racing a fair race," Pistorius said on-camera right after that race, charging that the blades Oliveira uses gave him an unfair advantage because they were too long. That accusation incited criticism because Pistorius himself has long dealt with non-disabled opponents claiming his own blades provide him an unfair competitive edge.
In his post-race comments Thursday, Pistorius went out of his way to praise Peacock.
"What we have seen tonight is a great Paralympic sprinter -- it was a great performance," Pistorius said. "The 100m is not my thing and it shows how much the sport has grown.
"I am unbelievably happy. Jonnie drew so much from the crowd. Well done to him and in front of a [...] home crowd. I'm sure this will be one of the memories of his life."
Pistorius' last chance for individual gold in London is the 400 meters, the same race in which he garnered headlines around the world during the Olympics last month for making the semifinals.
In the Olympic prelims last month, Pistorius ran the 400 in a season-best time of 45.44 seconds. If he can duplicate that time in the finals of the Paralympics later this week, he should have no trouble salvaging his first individual gold of the week.