PARIS, France (AFP) — The Paralympic amputee sprinters burst into action on Sunday and Britain chased China’s medal haul with a golden success in the pool and on the track.

There was a setback, though, for the organizers who were forced to delay the triathlon events by 24 hours due to concerns about the water quality of the River Seine after heavy rain.

The triathlon will now take place on Monday after tests proved the water quality was at acceptable levels following a warm and sunny day in the French capital on Sunday.

China set the pace again on the fourth day of competition to amass 33 gold medals but Britain moved onto 23 golds after bagging 12 golds on Sunday, the country’s best performance on a single day at a Paralympics this century.

The United States and Brazil both have eight golds.

One of the outstanding British successes came from wheelchair racer Hannah Cockcroft who made it four titles in the women’s T34 100 meters in four Paralympics stretching back to London 2012.

Cockcroft said she had been boosted by the roars of the estimated 50,000 crowd at the Stade de France.

“My wheels were vibrating!” she said.

“They said ‘On your marks’ and it didn’t go quiet.”

“I was afraid I wasn’t going to hear the gun. But this is what we want, it’s fantastic.”

“It means so much to get a fourth gold,” she added, and pledged to keep competing until the 2028 Los Angeles Paralympics — but her immediate priority is her wedding to fellow British Paralympian Nathan Maguire later this year.

In the pool, British swimmer Maisie Newton Summers won her second gold medal of these Games by taking the SB6 100m breaststroke title.

Britain also won three golds in the track cycling as well, but China’s excellence across a wide range of sports kept them out in front, with eight golds so far in swimming alone. Yang Hong winning the men’s SB6 breaststroke title was among their haul in the pool.

Italy’s Maxcel Amo Manu set the pace when the amputee sprinters strapped on their blades and roared into action, while social media sensation Hunter Woodhall scraped into the final.

Manu, who won the world title last year, set a new Paralympic record of 10.69 seconds to lead all qualifiers in the men’s T64 100m.