Three-time Wimbledon champion John McEnroe has told Rafael Nadal to "get a new damn coach".
The 14-time Grand Slam champion has failed to make it past a major quarter-final this year after losing to Wimbledon qualifier Dustin Brown.
McEnroe said the 29-year-old should drop his long-term coach, uncle Toni Nadal after his second-round exit.
"It might be time for some fresh blood in the Nadal camp," McEnroe said on BBC Radio 5 live's 6-Love-6.
Nadal lifted the title on Centre Court in 2008 and 2010, but has not progressed past the fourth round since losing the 2011 final to Novak Djokovic.
The Spaniard has said his best days at Wimbledon may be behind him, and McEnroe feels it is time for change.
The 56-year-old added: "Are we even allowed to say that? Uncle Toni's going to be upset.
"I know Carlos Costa, who manages Nadal, and he's had other people.
"They have tried to gently persuade Uncle Toni - who has done a magnificent job from when Rafa was a little kid. Clearly at this stage it would appear that some fresh ideas are in order."
German world number 102 Brown faces Serb Viktor Troicki in round three on Saturday,
McEnroe wants the 30-year-old to build on his victory over Nadal, adding: "That to me has got to be one of the all-time great performances you'll see from a total unknown."