The 43-year-old is in Berlin for the Laver Cup – the Ryder Cup of tennis – where Team Europe will clash against Team World.

With world No 1 Jannik Sinner and Spanish superstar Carlos Alcaraz cleaning up the Grand Slams this year, the Swiss great, who announced his departure from the sport in 2022, admits players are becoming more “fearless” in their approach due to the greater reward.

“The guys and also the ladies are going to start hitting bigger forehands and backhands, be more fearless because they realise the reward is there,” Federer told a news conference in Berlin.

“The best movers are the best players and you can see that. The mentally fittest, physically strongest and fastest are the best players.

“It’s not so much about technique any more. I’ve got fooled enough in the last 10, 15, 20 years where I think, ‘I’m not sure about this technique’ but with racket technology and string technology you can iron those problems out and so long as you hit hard and nice through the ball, everything is possible in tennis to be honest.

“The game is where it was, but just a step higher. I always feel like it keeps on going up.

Perhaps maybe just a lack of variation but that’s because we have all double-handers these days and they don’t use the slice as much.