A psychologist has urged TV commentators and fans not to mock Rafael Nadal's repetitive mid-match "routines" because the world number one may be showing signs of obsessive-compulsive behaviour.
Christopher Mogan complained to broadcaster Channel Seven after coverage focused on Nadal's habits, which include lining up his water bottles with the labels facing a certain way.
"What upset me is that I think it's known that Rafa has obsessive-compulsive indications," he told The Age newspaper.
"Two to three percent of people have this seriously disabling condition and they would be identifying with him -- when he does his square walk... how he places his bottle in a row, very carefully.
"They are routines, but the point is they're meant to try and control anxiety. It's about getting a 'just right' feeling: 'I can feel just right if I line my bottles up.'"
The 13-time Grand Slam-winner goes through an identical routine before every serve, involving pulling at the back of his shorts and touching each shoulder, both ears and his nose.
He also refuses to step on lines between points, and Lleyton Hewitt told a story during the Channel Seven coverage about how Nadal takes his shirt on and off repeatedly before leaving the locker room.
"It's being highlighted, and it's disrespectful to him," Mogan said. "(Obsessive-compulsive disorder sufferers) would be very distressed by that, that they were being laughed at, basically.
"(OCD) is a mental illness, one of the most common anxiety disorders."
According to The Age, a member of Nadal's camp dismissed any concerns and his coach, his uncle Toni, has said the behaviour is merely superstition.
He is not the only player with repetitive routines. Maria Sharapova goes to the back of the court and stares intently at her racquet between points, and Andy Murray wipes his face with a towel.
Mogan, who said he could not diagnose Nadal without speaking to him, also acknowledged that he could be displaying "perfectly controlled behaviour that belongs only on the tennis court".
"It is possible it could be just a manifestation of the control athletes seek to get," he said.