A psychologist has urged TV commentators and fans to stop mocking Rafael Nadal's repetitive mid-match "routines" because the world No 1 might be showing signs of obsessive-compulsive behavior.

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.