London, February 17: Twenty-time Grand Slam champion Roger Federer has become the oldest world number one after he defeated his Dutch opponent Robin Haase at Rotterdam's ABN Amro World Tennis Tournament.

According to the Sky Sports, the Swiss great secured his spot in the history books and the last four of the tournament with a 4-6 6-1 6-1 victory against Haase on Friday.

The 36-year-old became the oldest No. 1 male player, surpassing eight-time Grand Slam winner Andre Agassi, who holds the record at 33 years since September 2003.