Argentine soccer legend Diego Maradona has mourned the death of longtime friend Fidel Castro, likening him to a second father.

"The day is horrible, last night they told me that the greatest died, the greatest without a doubt. Fidel Castro left us. They called me from Buenos Aires and it was very shocking. I felt terrible pain because he was like my second father," he said speaking to reporters in Zagreb, Croatia where he was cheering on Argentina in the Davis Cup tennis tournament.

Maradona joined scores of world leaders honouring Castro. And he had strong words for many critics who labelled him as a "tyrant".

"I have not spoken with anyone because it is very heavy, everything that is happening. And it is very painful. I was watching television before coming here. A death is being celebrated. It is very painful, it is very sad, it's disgusting, it is truly disgusting. What Fidel did was fight for his own people and and if the worms [referring to anti-Castro Cubans in the U.S.) didn't like it, well, I'm sorry, but it seems to me that to be celebrating a death is very sad," he said.

Castro and Maradona had a close relationship. In January of 2015, Maradona told Venezuelan TV that Castro had sent him a letter to quash death rumours.

In 2014, Castro congratulated Maradona for his television program analyzing the World Cup.

Castro helped Maradona recover from substance abuse and a weight problem when he went to Cuba for help in 2000.