In January, Roger Federer set a new record for most singles Grand Slam titles, winning his 20th at the Australia Open.
However, there's a good chance he'll break another record in a few weeks' time after accepting a late wildcard entry into the ATP tournament in Rotterdam, Netherlands, which is held from February 12-18.
A semifinal appearance at the tournament would see Federer, 36, become the oldest men's world No.1 in history, surpassing the mark set by Andre Agassi, who reached the top ranking in 2003 at 33.
Current world No.1 Rafael Nadal would lose the top seeding for the moment should Federer reach the semifinals, with the Spaniard not set to compete again until late February, after the Rotterdam event.