It has been confirmed that Roger Federer has returned to world number one after the new ATP world rankings were released on Monday.

The Swiss player becomes the oldest holder of the number one position in the modern era at 36 years and 279 days old after Spaniard Rafael Nadal dropped to second place following his defeat to Dominic Thiem in the Madrid Open quarter-finals on Friday.

Federer was number one for four weeks earlier in the year and he first held the number one position when he was 22 in February 2004. The time between then and now is the longest gap between a player holding the top ranking. Federer has spent an incredible 309 weeks at the top of the ATP world rankings.

Federer decided to miss the whole clay-court season and has returned to the top of the rankings without playing a single match. He will return for the grass season at the Mercedes Cup in Stuttgart on June 11th.

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Nadal has the chance to take back the top spot before the grass season begins if he wins the Rome Masters this week and the French Open, which begins on May 21st.

Former world number one Novak Djokovic has dropped out of the top 115 for the first time since 2007.

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Djokovic underwent elbow surgery after his defeat to Chung Hyeon in the Australian Open, and on his return, he has suffered some early round defeats.