Thomas Young and Sophie Hahn give Great Britain a golden day on the track

Defending champion Hahn, who has cerebral palsy, had equalled her own world record of 12.38secs in the heats and once again showed her class.

While she could not quite replicate that rapid pace in the decisive race, the 24-year-old from Nottingham held off a strong surge from Colombian silver medallist Darian Faisury Jimenez Sanchez – who very briefly snatched her Paralympic record earlier in the day – to cross the line in 12.43s.

Fellow Britons Olivia Breen and Ali Smith finished sixth and eight respectively in 13.13 and 13.24, while Germany's Lindy Ave won bronze.

"The build up was quite tough with all the expectation but I tried to stay calm and focused," said Hahn.

"That's definitely that hardest I've ever been pushed. She was hot on my heels and I really thought it would be a photo finish but to see my name was absolutely incredible.

"I saw Thomas and that really spurred me on. That's an incredible time to go and I'm so pleased for him."

Young was diagnosed with neurofibromatosis shortly after London 2012, a genetic disorder of the nervous system which affects his coordination.

He picked an opportune moment to dip below the 11-second mark for the first time in his fledgling career, significantly bettering his qualifying time of 11.22 to usurp title favourite Zhu, with moustachioed Australian Evan O'Hanlon third.

"It's the best feeling in the world. The time is a bonus, I just wanted to win but having that personal best just makes it even better," said Young.

"I wanted to be a dominant force in this sport, I know Paris (2024) is next but I'm already thinking about Brisbane (2028). Any kid growing up in this sport was inspired by Usain Bolt and he's got three golds and I'd like that too."

Also on Saturday, two-time silver medallist Stef Reid was unable to repeat her achievements from London and Rio.

The New Zealand-born athlete, who lost her right foot in a boating accident aged 16, finished fourth in the T64 women's long jump after a season's best 5.75 metres as Fleur Jong of Holland won gold with a world-record leap of 6.16m.

"Coming fourth is kind of bittersweet. But I'm so proud of turning my season around. It was a massive season best for me," said Reid.

"It's been a long time since I've been at a meet of this calibre. Two women over six metres is huge. It is exciting watching all these young athletes coming up. The standard keeps rising."

Earlier, David Devine finished just outside the podium places in the men's T13 5000m final.

The visually impaired runner from Liverpool was fourth in a season's best 14mins 38secs, just over half a second off claiming the third Paralympic bronze of his career.

"The plan was always to hit the front with two laps to go but with 300m to go, I just didn't have enough in my legs. It was so hot out there – which is the same for everyone," he said.

"Since (London) 2012 where I got two bronzes, I've missed every world championships because of injury, I missed Rio because I was sick.

"In the last nine years I have done two European championships. No offence but that is a level down, so I'm really proud of myself to get back to this level and be challenging for medals."

Elsewhere, Luke Nuttall – son of Olympians John Nuttall and Alison Wyeth – was ninth in the men's T46 1500m final.

The 19-year-old said: "On reflection, the experience will be really good and will be valuable with Paris only three years away."