Former world number one Boris Becker has called on tennis players under the age of 28 to "show up" and start challenging for Grand Slam titles.
With Nadal winning the French Open, the last 10 Slams have been won by either the 33-year-old, Novak Djokovic, 32, or Roger Federer, 37.
Dominic Thiem, 25, is the only male player currently aged under 28 to have reached a Grand Slam final.
"That is not good," six-time Grand Slam champion Becker said.
"That is not a compliment for anybody under 28.
"And don't give me that the others are too good.