Nick Kyrgios could be in trouble for reportedly calling his entourage "retarded" for not cheering him on to his satisfaction.

The claim comes as he battles with Feliciano Lopez for the second day after yesterday's match was postponed due to poor light.

Seeded 15th, the 21-year-old grew angry as Lopez made a comeback after he had won the first set 6-3 and would subsequently lose the second one 6-7. He told his entourage to either cheer him on or leave the court and later reports suggested he had referred to them as "retarded".

This comes on the back of his fellow Australian, Bernard Tomic, saying he felt like a "retard" when an opponent was slow to walk out on the court with him and has since apologised.