The 2015 Summer Universiade in Gwangju, South Korea, was where China's Shuyin Zheng won her first senior international taekwondo gold - a year before she became Olympic heavyweight champion in Rio de Janeiro.

Zheng - who had won world and Olympic gold at youth level in 2010 - earned her landmark title with a 4-0 win in the women's under-73 kilograms final against Croatia's Iva Radoš, who she had beaten earlier that year 8-1 in the semi-finals of the Chelyabinsk World Championships before losing 5-4 to South Korea's Oh Hye-ri in the final.

Before the 2015 season was over Zheng earned a 4-1 win in the Manchester Open over local athlete Bianca Walkden, who had won the heavyweight title in Chelyabinsk.

In 2016, the two met in the Olympic semi-final of the over-67kg category, with Zheng going through 4-1 on superiority before beating Mexico's Maria Espinoza 5-1 in the final.

At the following year's World Championships, Zheng took bronze in the over-73kg class, and in 2018 she won the Grand Prix final at Fujairah.

Earlier in the 2018 season she had beaten Walkden 6-4 in the Manchester Grand Prix final - but in 2019, when the northern British city hosted the World Championships, the venue would provide her with her least pleasant memory in the sport. 

Despite being 20-10 up against home fighter and defending champion Walkden in the women's heavyweight final, the Chinese Olympic champion was disqualified for incurring ten fouls after her opponent had repeatedly pushed her off the mat.

The tactic employed by Walkden, who thus earned her third consecutive world title, was considered unsportsmanlike but was nevertheless within the rules, and the British athlete was quite satisfied with the outcome, declaring: "I wouldn't have it any other way".

Walkden's change of tactic had occurred after Zheng, who had already accrued seven penalty points, had become inactive after taking a ten-point lead. When the result was announced there was booing in the arena, and Zheng's coach gave the officials a thumbs-down sign.

But after the Chinese athlete had dropped to her knees on the podium, Britain's performance director Gary Hall took issue with her "disrespectful manner".

Walkden defended her tactics, saying: "I went out there needing to find a different way to win and a win is a win if you disqualify someone - it's not my fault."

Zheng, meanwhile, told Chinese media: "From the first day I picked up this sport, I understood that there was no such thing as absolute fairness in competition. I have been doing this sport for 16 years but this is the first time I have realised that a taekwondo match could be played like this.

"I wish the referee could have been fair in this competition."

A Chinese appeal, and demand that the Moroccan referee, Tarik Benradi, be banned for life, were unsuccessful.

Zheng, however, recovered from her trauma to beat Walkden in the final of the next two Grand Prix events in Chiba and Sofia - by 12-10 and 3-2 - before winning the Grand Prix final in Moscow 7-4 against Serbia's Milica Mandić.

Her final action of the year, however, saw her beaten 2-0 by Walkden in the semi-final of the Wuxi Grand Slam event.

It is one of taekwondo’s enduring rivalries…