The London 2012 Olympian's rapid combinations saw him outbox his opponent for much of the fight and despite being caught with a powerful shot in the fifth round, Melian stayed on his feet and maintained his composure to pick up the win on the judges' scorecards. 

"I am really happy about my victory and I would like to thank everybody who came to support me tonight," said Melian after overcoming Njangiru, a bronze medallist at this year's Commonwealth Games.

"APB is a real pro competition, and all the opponents are really strong, however, I realise that my previous experience, including WSB (World Series of Boxing) helped me a lot in this victory."

In one of the biggest surprises of the APB so far, Azerbaijan's Javid Chalabiyev, the number two seed and reigning AIBA world champion, lost his first match in the competition to Brazil's two-time Olympian Robenilson Vieira de Jesus.

Chalabiyev entered the contest as a big favourite but the elusive style of De Jesus proved to be a real surprise and the Brazilian managed to use his trickiness to counter the aggressiveness of the Azeri athlete.

As the fight wore on, Chalabiyev worked ever harder to claw back some points but the more he tried, the less he could work out, as De Jesus counter-attacked magnificently all the way to a surprise victory.

Number one seed Khedafi Djelkhir, who was making his APB debut with a 16-0 professional record and 12 stoppage victories behind him, was too strong for Venezuela's Yonni Blanco.

The Frenchman's  experience shone through in the fight, as he maintained a vigorous tempo that was simply too much for the courageous Blanco, who never wilted in effort despite the disparity in quality.

Brazil's Robenilson Vieira de Jesus (left) registered a shock victory against Azerbaijan's Javid Chalabiyev (right) ©AIBA Pro Boxing



All three judges gave the fight to the 2008 Olympic silver medallist, who has laid down a marker for the rest of the competition.

"I would say that I managed to win this fight quite easily and it is due to the great work of my coaches and my team," said Djelkhir.

"APB is a great competition as it represents evolution for boxers."

In the one other bout, China's Jiawei Zhang upset the odds to beat Russia's Sergey Vodopiyanov, a gold medallist at the 2007 AIBA World Championships and silver medallist at the 2009 edition.

The two-time Asian Games silver medallist exhibited aggressive boxing round after round and caught his decorated opponent off guard from the outset.

And although Vodopiyanov rallied towards the end of the fight, it was the Chinese star who prevailed.