World No 1 Naomi Osaka refused on Wednesday to become embroiled in a dispute with one of her former coaches who is suing her for 20 per cent of her career earnings.
Christophe Jean, who helped the Japanese two-time grand slam champion when she was a junior, wants at least $2 million (Dh7.35m) of the $10m of her earnings to date.
Jean insists Osaka's father, Leonard Francois, had signed a contract when he was coaching the 21-year-old and her sister Mari in 2011.
Osaka told AFP she was "not allowed to say anything" about reports of the lawsuit, although sources close to the Japanese star stressed they are not fearful of the outcome and believe the matter will be resolved shortly.
When asked about the difficulty of dealing with the trappings of fame and becoming the world's top player, however, Osaka admitted she is still learning.
"I am still relatively new at this so I can't really say yet," she said. "But maybe as more time goes on I will be able to get a better grasp of the situation."
Osaka spoke as tournament play began at the Miami Open, being staged at Hard Rock Stadium for the first time after decades at Key Biscayne.
TMZ, which reported the lawsuit, says Osaka attorney Alex Spiro calls Jean's claim "absurd" and adds: "This case has no merit and we will move past it."