Roger Federer is to undergo further knee surgery to give himself a “glimmer of hope” of returning to tennis.

The procedure is set to keep the 40-year-old out for “many months”.

Here, we take a look back at Federer’s remarkable career in numbers.

20 – grand slam titles, the most won by any man – a record shared with Rafael Nadal and Novak Djokovic.

31 – grand slam finals.

23 – consecutive appearances in grand slam semi-finals, an all-time record.

36 – consecutive appearances in grand slam quarter-finals.

65 – consecutive grand slam appearances from the Australian Open in 2000 to the French Open in 2016.

8 – Wimbledon titles, the most of any man.

6 – Australian Open titles.

5 – US Open titles.

1 – French Open title.

1,251 – career matches won out of 1,526.

369 – match wins in grand slams.

310 – weeks spent at world number one, 237 of them consecutively.

36 – at 36 years and 320 days, Federer was the oldest world number one in ATP history.

5 – Federer has reached the final at every grand slam at least five times.

103 – career titles, second in the Open era behind Jimmy Connors.

6 – titles won at the ATP Finals, an all-time record.

10 – titles won at the ATP events in Basel and Halle.

12 – titles won in 2006, his most successful season.

92 – matches won from 97 played in 2006.

65 – consecutive matches won on grass from 2003 to 2008.

4 – Federer reached the finals of all the grand slams in three different seasons.

2 – Olympic medals; gold in doubles with Stan Wawrinka in 2008, silver in singles in 2012.

24 – losses to his great rival Rafael Nadal from 40 matches.

130,594,339 – career prize money (US dollars).