Olympic boxing witnessed the rare sight of two Cubans fighting each other in the ring at the Rio Games on Tuesday with the winner securing a medal for Azerbaijan.

Lorenzo Sotomayor Collazo, the Havana-born cousin of Cuba's 1992 Olympic high jump champion Javier Sotomayor, was fighting in the red corner for Azerbaijan against Cuban light-welterweight Yasniel Toledo.

Sotomayor, a leggy 31-year-old with a long reach and elastic movement, won the quarter-final on a unanimous points decision to be sure of at least a bronze.

A Cuban national champion in 2009, he took the Azeri title in 2014 after a move to Baku.

Countries can have only one boxer representing them in each weight division at the Olympics, providing they qualify, and the competition for a slot is intense in a country like Cuba that boasts a proud history in the sport.

"At the end he just said 'thanks' and that was it," said Toledo of his opponent, who made a quick getaway without speaking to reporters.

After an earlier fight, Sotomayor had spoken a few phrases in Azeri to that country's media and briefly confirmed his background details to Reuters.

"These things happen. I wish him all the best and that things work out well," said Toledo, a lightweight bronze medallist four years ago. "He was better, he did his work well and in the end he deserved the win."