Madrid - Rafael Nadal's coach and uncle Toni Nadal has criticised the 12-time Grand Slam champion's attitude after he suffered a shock first round exit from Wimbledon on Monday.
The Spaniard was beaten 7-6, 7-6, 6-4 by world number 135 Steve Darcis to suffer his first ever defeat in the first round of a Grand Slam.
And the defeat came as an even greater surprise as Nadal had been in sensational form since returning from a knee injury in February, winning seven titles and reaching the final of the other two events he had taken part in.
However, all but one of those tournaments came on Nadal's preferred clay court surface and Toni Nadal believes his nephew lacked the same belief on the grass courts of the All England Club.
"For me, what failed him most was his attitude. It is because of this we lost," he told Spanish media at a sponsor's event on Wednesday.
"He didn't face up to the game well. After a break of seven months, returning with many doubts, making a great effort and everything going very well, I think Rafa dropped his intensity a little."
Nadal also suffered a shock defeat at Wimbledon last year to the unheralded Czech Lukas Rosol and his coach admitted the world number five was having problems adjusting to the quicker conditions on the grass.
"Things on this surface right now aren't going as well as on other surfaces. It is true that his movement wasn't good and that everything is a little bit more difficult.
"In other places you decide to keep going, fight and in the end, in the best case scenario, you can win. Here if you see yourself as less of a winner then it makes things more difficult for you and that's why I tell you that the attitude wasn't the best."
The 27-year-old has returned to his homeland for a short break before attention turns to the hard court season ahead of the US Open in September.
However, he could make one more appearance on the clay in Stuttgart or Hamburg in July before making the trip across the Atlantic for Masters Series events in Montreal and Cincinnati ahead of the fourth Grand Slam of the season in New York.