Gitinov, one of the many Russian-born fighters competing under the flag of Bahrain, was the first winner from the 2019 World Championships to enter the cage here.

Wearing gold, as is his right as a world champion, he claimed a clinical win over Tomas Markus of Lithuania to move into the quarter-finals.

Rated as one of the best pound-for-pound MMA fighters, Gitinov reined down punches to the back of his opponent's head in round two, prompting the ref to step in for a TKO.

Elsewhere, three champions from September's World Cup in Prague were sent tumbling out of the competition at the last 16 stage.

Mansur Magomedov, another of the Russian-born Bahrain fighters and winner of the flyweight title in the Czech capital, failed to return from his stool at the end of round one against Mexico's Jorge Antonio Lopez because of an apparent shoulder injury.

Lopes leapt into his coach's arms in celebration as the noisy Mexican contingent celebrated wildly in the stands.

Jordan's middleweight World Cup winner Hazem Kayyali was hotly tipped to do well here but was outclassed by New Zealand's Fergus Jenkins to exit the Championships.

Ivan Kurelaru, the lightweight winner in Prague, also went out as he lost by split decision to Bahrain's Kurban Idrisov.

Elsewhere, there was a sad end for Japan's featherweight Reo Yamaguchi as he was stretchered out of the arena.

The popular figure has lost a trilogy of junior IMMAF finals to England's Muhammad Mokaev, now a Ultimate Fighting Championship (UFC) prospect, with many hoping that his time would come in Abu Dhabi.

However, he was second best against Spanish World Cup champion Juan Izquierdo and his corner stopped the fight at the end of round two with ice packs being applied to his shoulder.

Heavyweight favourite Rasul Magomedov began strongly for Bahrain with the World Cup and European Open winner earning a unanimous decision over Kosovo's Arlind Berisha after regularly taking his opponent to the mat.

Italy's bantamweight World Cup winner Fidel Gramiccia also marched on to the quarter-finals after getting the verdict from all three judges against French Polynesia's Keoni Terorotua.

The first women's matches of the Championships took place with Ireland's Kerry Ann Vernon, the World Cup silver medallist, impressing thanks to some powerful punches which busted the nose of Slovakia's Elina Tauber en-route to a unanimous victory.

There was also unanimous decision success for Tajikistan's Jovidon Mahmudov, the welterweight World Cup winner who at one point carried Italy's Dario Petrolo across the cage before slamming him down.

It was a day of fantastic submissions including a buggy choke from Kazakhstan's Bogdan Pshebelskiy in his welterweight win over Tymur Kurbankadiiev of Ukraine.

The complicated hold has never been performed successfully at an IMMAF event before.

Australian Troy Fumo won in the strawweight class with a Von Flue choke, a shoulder move named after Jason Von Flue who invented it in the UFC.

Bahrain's Murad Guseinov claimed his second quick submission win in as many days as he backed up his neck choke win over Sweden's Linus Lindeberg yesterday by beating Ireland's Adam McEnroe via arm triangle.

Big TKO finishes came from the likes of German heavyweight Tom Hoelemann, who flattened Konstantin Rakhimov of Kazakhstan with a massive kick to the head in round one.

A huge right hand from Indian middleweight Ramston Edwin Rodrigues, who has trained with Conor McGregor, sent Lukas Piffko of the Czech Republic to the canvas and Swedish light heavyweight Robin Enontekio wiped out Guyana's Ijaz Cave with a beautiful left.

The World Championships are due to resume tomorrow with quarter-final bouts across the weight divisions.