Roger Federer revealed he will miss the rest of the 2020 season after needing an additional surgery on his problematic right knee.
The Swiss maestro, who turns 39 this summer, went under the knife in February for arthroscopic treatment.
It initially looked as though Federer had inadvertently timed his operation to perfection with the tennis season halted soon afterwards during coronavirus.
But he took to Twitter to tell fans he had to have further an extra procedure as his recovery hit a stumbling block.
And that ruled him out of both the US Open and rescheduled French Open, which are still on course to be staged later this year.
Instead, the 20-time Grand Slam champion is focusing on getting himself fully fit again for the start of the 2021 season.
Federer wrote: “Dear Fans. I hope you are staying safe and healthy.
“A few weeks ago, having experienced a setback during my initial rehabilitation, I had to have an additional quick arthroscopic procedure on my right knee.
“Now, much like I did leading up to the 2017 season, I plan to take the necessary time to be 100 per cent ready to play at my highest level.
“I will be missing my fans and the tour dearly but I will look forward to seeing everyone back on tour at the start of the 2021 season.
The news comes just days after Federer’s coach Severin Luthi let out the recovery process was not going as smoothly as hoped and he faced a race to be fit for Flushing Meadows, which kicks off on August 24.
Luthi said: “Roger’s recovery is not going as well as we expected. It is slower than we thought.
“I believe that we can see some action again from that month. We are hoping for that.”
The world No4 told fans in May he hadn’t been hitting – but insisted that was because he wanted a break while he had the chance rather than because of his body.
He said: “I’m not training at the moment because I don’t see a reason for that to be honest.
“I am happy with my body now and I still believe that the return of the tour is a long way off.
“And I think it’s important mentally to enjoy this break, having played so much tennis.
“When I’m getting towards returning and have a goal to train for, I think I will be super motivated.”