London (CNN) -- South African double-amputee sprinter Oscar Pistorius, who made headlines at the Olympics, set a world record on Saturday in London in defense of the first of his three Paralympic titles.
On day three of the Games, he ran 21.30 in men's 200m-T44 title in the first round Saturday evening, easily besting other racers in his heat. The paralympic movement classifies events, using terms like T44, to group competitors based on their disability.
His biggest threats in Sunday's gold-medal final will include Brazilian Alan Fonteles Cardoso Oliveira, American sprinter Blake Leeper and South Africa's Arnu Fourie, based on their qualifying times.
Pistorius, who uses carbon fiber prosthetic blades, made it to the semifinals of the individual 400-meter and the 400-meter relay final at the Olympics last month, running against able-bodied athletes.
In the Paralympics, which are the also being held in London, Pistorius is also competing in the men's 100-meter-T44 (set for next Wednesday and Thursday) and the 400-meter-T44 (happening Friday and Saturday), both of which he won in Beijing four years ago. He's also part of South Africa's 4 X 100-meter T42/T46 relay team, which is scheduled to race Wednesday.
Competition was intense Saturday in Paralympic competitions in and around Great Britain's capital, with 49 gold medals on the line across seven sports, including athletics, track cycling, swimming and equestrian.
Britain's Richard Whitehead sprinted to victory earlier Saturday in the men's 200m - T42, setting a new world record in the process and shedding tears of joy at the finish. Team USA's Shaquille Vance took the silver medal.
There was also drama in the velodrome Saturday.
Britain's Neil Fachie, piloted by Barney Storey, smashed the world record to earn gold in the men's individual B 1-kilometer time trial, an event on a tandem bicycle for the visually impaired.
There was bitter disappointment, though, for the cyclist whose record he took. World champion and fellow Briton Anthony Kappes, piloted by Craig Maclean, had his medal hopes dashed after the chain on their bike failed twice.
Britain's Sarah Storey, wife of Barney Storey, made it a double gold for the household Saturday with victory in the women's individual C4-5 500-meter time trial, while U.S. cyclist Jennifer Schuble took silver.
The win gave Sarah Storey, who was born without a functioning left hand, her second gold of the Games and an impressive 20 Paralympic medals in total across the swimming and cycling disciplines. She has also competed successfully against able-bodied athletes.
Gold medal in the men's individual C4 cycling pursuit went to Carol-Eduard Novak from Romania, with silver for Jiri Jezek of the Czech Republic. Britain's Jody Cundy took bronze, a day after he was disqualified for a false start in the time trial.
Australian world champion Michael Gallagher won the men's individual C5 pursuit, holding Britain's Jon-Allan Butterworth, a military veteran who lost an arm to a rocket attack in Iraq five years ago, to second place.
China's Yin He set a world record in the women's C1-2-3 500-meter time trial to take gold.
There is a tense wait ahead for Team USA's 17-year-old Victoria Arlen, who earlier this week was ruled ineligible to swim at the Games by the International Paralympic Committee.
Arlen's appeal against the ruling was upheld Thursday, meaning she could swim in Saturday's 400-meter freestyle heats -- winning hers by a convincing 19-second margin -- but her classification is still subject to review by the IPC.
British medal hope Ellie Simmonds, also 17, won her heat in a time a fraction faster than Arlen, the world record holder. That order held up in the finals, with Simmonds setting a world record in finishing a second ahead of Arlen -- with the two of them both 13 seconds faster than any other competitor.
Arlen's classification problems came after fellow U.S. Paralympians Justin Zook and Mallory Weggeman were reclassified earlier this week. Arlen, from New Hampshire, was a talented able-bodied swimmer until a neurological disease left her paralyzed in both legs.
The complex system of disability classification, which ensures athletes compete against those who are similarly-abled, is considered an essential tool for the Paralympic movement.
On the track, the crowd gave a huge reception to Houssein Omar Hassan, who entered the Games on a wild card and is Djibouti's first Paralympic runner. He finished nearly 7 minutes behind the next slowest competitor in the 1,500-meter race but was applauded for his spirit in finishing.
Over at Eton Manor, the first Paralympics-only venue to be built for the Games, the Netherlands' wheelchair tennis star Esther Vergeer is looking to extend her decade-long dominance of the sport.
Vergeer -- who already has five Paralympic wheelchair tennis titles, three in singles, two in doubles -- beat Japan's Kanako Domori in straight sets in the first round of the women's singles. The rules for this competition are almost the same as for able-bodied tennis, but the ball is allowed to bounce twice.
In another display of dominance, Nigeria took its fifth powerlifting medal of the Games on Saturday, compliments of Esther Oyema in the women's -48 kilograms competition.
CNN's Tom McGowan contributed to this report.