London: Indian boxer Vikas Krishan who was earlier declared winner has crashed out of the games after the decision was reversed in the favour of his American opponent Errol Spence.

The 20-year-old Krishan kept himself in medal reckoning in his 69 kg category bout by scripting a hard-fought 13-11 victory over Spence in a thrilling pre-quarter final contest.

"There were a total of nine (9) holding fouls committed by the Indian boxer in the third round alone. However the Referee only gave one caution," the AIBA said in a statement after a review by its Competition Jury.

"In the second round, at the time 02:38, the boxer from India spitted out his gumshield intentionally. However the Referee didn't give any warning," it added.

Based on these "findings", the jury members "unanimously" decided to award Spence four points, thereby making him the winner.

"Based on the AIBA Technical & Competition Rules 12.1.9, the Referee should have given at least two (2) warnings to the Indian boxer. Although the boxer from India intentionally spitted out his gumshield, the Referee's view was blocked by the boxer from the USA and was not able to see the action," it international body said.

"...At least four points should have been awarded to the boxer from the USA. Therefore the final score should be 13:15 in favour of the USA. The protest is accepted and the winner of Bout 142 is Errol Spence (USA)," the AIBA statement added.

Vikas, only the second Indian boxer after Vijender to fetch a bronze medal in the World Championship, was among the biggest medal prospects for the country.

Spence advanced into the quarterfinals to face Russia's Andrey Zamkovoy on Tuesday.

Krishan, the world number six seeded three in this Olympics, had gotten a bye to the round of 16.