Australia's Paige Greco won her first gold medal in cycling at the Tokyo Paralympics, defeating China's Wang Xiaomei in the women's C3 individual pursuit to win gold in a new world record.

The 24-year-old South Australian native broke three world records in two days at the 2019 UCI Para Cycling Track World Championships in the Netherlands, catapulting her to the sport's top level. One of those records was in the C3 Individual Pursuit, with a time of 4:00.206. But the reigning world champion in this event broke that time twice, in Wednesday's qualifying and gold medal finals, setting a new record of 3:50.815.

"I'm so happy, I can't believe it," a tearful Greco said in an interview with Australian broadcaster Channel Seven shortly after her win.

Dennis Schindler (Germany) won the bronze medal ahead of Clara Brown (USA).

Class C is for athletes with disabilities that affect coordination, such as missing limbs, impaired strength or range of motion, uncoordinated movements or involuntary movements, and is subdivided into C1, C2, C3, C4, and C5 depending on the degree of disability.

Greco, who has cerebral palsy, competed in two 100-200m sprint events in para-athletics, but switched to cycling five years ago after being pointed in that direction at a talent search day. She now represents Australia in both track and road races.

"When I started competing, I was really into 500 meter time trials, but then my coach at the time told me to do 3 km and road.

"So now I focus more on endurance and I love long, long rides on the bike."

Shortly after Greco's win, Emily Petricola won gold for Australia in the C4 individual pursuit final at the Izu Velodrome. American Sean Morelli won the silver medal, and Canada's Keely Shaw took the bronze.

Other medal finals on the track on Wednesday included the women's C5 individual pursuit, where Great Britain's Sarah Storey added another gold medal to her extensive collection, and compatriot Crystal Lane-Wright took silver.

And in the Men's B 4000m Individual Pursuit, visually impaired athletes compete in tandem with sighted pilots. Tristan Vamma of the Netherlands won gold, Stephen Bate of Great Britain won silver, and Marcin Polak of Poland won bronze.

Track events continue through Saturday, August 28. Road competitions begin on Tuesday, August 31, starting with time trials and ending with the final road race on Friday, September 3.