Tennis news - Roger Federer undergoes knee surgery, out until 2021

In a social media post, the current world number four wrote that he had an arthroscopic procedure - and would be taking the rest of the year off to recover fully.

He added: "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 Swiss star, who turns 39 in August, had initially had surgery on his troublesome knee in February, and had hoped to return in time for the grass court season.

Federer had a similar attitude to his rehabilitation in 2016, when he tore the meniscus in his left knee while running a bath for his children.

"Now, much like I did leading up to the 2017 season, I plan to take the necessary time to be 100% ready to play at my highest level," he added.

The suspension of the tennis tour had initially given him more time to recover, but with his beloved grass court season likely to be absent from the calendar, he has chosen to skip any events or exhibitions that might be scheduled for the rest of the year - and return in 2021 as he continues to chase a 21st Grand Slam title.