The 23-year-old middleweight twice knocked down his Serbian opponent in the final round on his way to securing a place in the last-eight with a unanimous points win at the Jose Maria Vargas Dome.

"My tactics always depend on my opponent’s style and skills, but I did not know the Serbian that well," said Sanchez Marte.

"I think I found a good rhythm, though, and now I am looking forward to my quarter-final contest."

The event is the only opportunity for professionals like Ajetovic, who at 35-years-old has a professional record of 28 wins, 15 defeats and one draw, to book their place at Rio 2016.

It follows a controversial ruling, passed unanimously at the International Boxing Association (AIBA) Extraordinary Congress on June 1, allowing National Federations to register all non-AIBA professional boxers for the tournament.

The decision to grant professionals the opportunity to compete at the Olympics has been heavily criticised, with possible safety risks due to mismatches between professional and less-experienced amateurs among the concerns.

However, former world heavyweight champion Mike Tyson claimed professional boxers would lose against amateurs, branding the idea of them competing at the Olympic Games as "ridiculous" and "foolish".

Today’s other two contests came at super heavyweight as Egypt’s Ahmed Samir Abdelmoaz Hefny and Ukraine’s Rostyslav Arkhypenko both reached the quarter-finals at the expense of Aruba’s Evan Nedd and the United States’ Brandon Lynch respectively.

Abdelmoaz Hefny won by split decision, while Arkhypenko triumphed on all three judges’ scorecards.

Tomorrow will see 18 contests held with boxers at flyweight, lightweight, light welterweight,welterweight, light heavyweight and heavyweight all in action.

A total of 26 quota places for Rio 2016 are up for grabs over six days of competition; three at each weight barring heavyweight and super heavyweight where only the winners will qualify.