Isayev indicated his potential at the 2013 World Championships in the Mexican city of Puebla where, aged 23, he took the bronze medal in the middleweight under-87 kilograms class after losing 3-2 in his semi-final to China's Ma Zhaoyong.

The following year, Isayev picked up what would be the first of his three – so far – continental titles when he won the European Championships on his home ground of Baku, earning a commanding 12-2 win in the final against France's Mbar Ndiaye. 

In 2015 he returned to the Azerbaijani capital to contest the first European Games – and did so as world champion, having won the middleweight title in the Russian city of Chelyabinsk thanks to two titanic victories. 

In the semi-final he defeated Cuba's defending champion, Rafael Alba, 7-6, and he then beat Uzbekistan's Asian Games champion Jasur Baykuzigyev 5-4 for gold.

Expectations were sky-high for the home athlete in the taekwondo-mad host city, and he rose spectacularly to the occasion, delivering the heavyweight over-80kg European Games title with a 4-3 win over Russia's Vladislav Lorin in front of a vociferous crowd in the Crystal Hall.

It was the perfect preparation for his first Olympic competition – and in Rio the following year he hit the mark again as he took gold with a 6-2 win over Niger's Abdoul Issoufou at the Carioca Arena 3.

Having lost in the round-of-16 at the 2016 European Championships, he returned to the gold standard in that competition when it was held in the Russian city of Kazan in 2018, beating home fighter Roman Kuznetsov 10-7 in the final.

Isayev exited at the round-of-16 stage in last year's Manchester World Championships, but recovered his momentum with bronze medals at the Chiba Grand Prix and the Grand Prix final in Moscow.

He indicated that he was still going strong with victories early in 2020 at the Helsingborg and Dutch Open before the coronavirus lockdown halted operations.