Controversial Australian star Nick Kyrgios has courted controversy in his first-round French Open clash with a foul-mouthed rant in which he accused experienced umpire Carlos Ramos of “unbelievable bias”.

Kyrgios was issued a code violation following a crucial point in his first-set tiebreaker with Italy’s Marco Cecchinato on Sunday for screaming for a towel from the ball boy at a wet Roland Garros.

The volatile 21-year-old took exception to Ramos’ ruling, arguing that he had raised his voice to get the ball boy’s attention purely because of the raucous atmosphere inside ‘the bullring’ as showcourt one is commonly known.

“Now I’ve really seen it all,” a mystified Kyrgios said to Ramos after being handed the code violation.

“What rules am I breaking?”

On his next service, Kyrgios was bugged by a member of the crowd who cheered support during his ball toss and again directed his complaints at Ramos.

“But that’s alright? Screaming out during my serve?” he queried.

He won that service point to go 4-2 up in the tiebreak, before resuming his verbal battle with Ramos.

“That’s f**king bulls**t,” Kyrgios barked, before referencing an incident in Rome last week where world No.1 Novak Djokovic pushed away the arm of chair umpire Carlos Bernardes during a win over Rafael Nadal.

“How can you sit there and give me a code for that?

“But when Djokovic pushes an umpire out of the way that’s alright? Tell the whole world that’s alright.”

As he took his place back on the court, Kyrgios directed his gaze at Ramos and said: “Unbelievable bias man. Unbelievable bias.”

The incident sparked the crowd, who had been largely subdued during the first set, into a chorus of boos – but Kyrgios recovered to take the first-set tiebreak 8-6 in 54 minutes.

Earlier the 17th seed had the crowd applauding following an act of good sportsmanship when he located a missing racquet dampener for Cecchinato.