Roger Federer believes old rival Rafael Nadal has adapted his game to cope with grass court tennis ahead of their Wimbledon semi-final meeting.

Swiss Federer, 37, and Spaniard Nadal, 33, play their tantalising semi-final on Centre Court, their first meeting at SW19 since an unforgettable 2008 final which Nadal won in five sets to claim his maiden Wimbledon crown.

Veteran Federer is aiming for his 21st Grand Slam title and will be meeting Nadal for the 14th time in the sport’s biggest events. It will be the 40th meeting between the pair in their illustrious careers, with Nadal ahead 24 to 15, though Federer trumps his rival with eight Wimbledon titles compared to two.

“Rafa has improved so much over the years on this surface. He’s also playing very differently,” said Federer. “I remember back in the day how he used to serve, and now how much bigger he’s serving, how much faster he finishes points.

“We have a lot of information on Rafa, as does he on us. So you can dive into the tactics like mad, or you say ‘it’s grass-court tennis so I’m going to come out and play my tennis’. “I’m excited to play him again.”

Nadal meanwhile admits it will be special for both men to return to Centre Court together, especially with time now running out on their respective careers. “The opportunities to play against each other are becoming less, but we are still here,” he said.

“I’m not expecting to learn new things about him. I just expect to play against probably the best player in history on this surface. “I know he’s playing well. He feels comfortable here. I’m playing well, too.”

Nadal is favourite at 1.67, while Federer is 2.10 to win. The Swiss is 5.50 to win in four sets.