Novak Djokovic has already guaranteed his place at the ATP World Tour Finals in London later this year.

17120 - Novak Djokovic books London return

The world No. 2 clinched a seventh successive title of the season, beating Rafael Nadal in the final of the Rome Masters to take his unbeaten start to the season to 37 matches.

Djokovic has already amassed 6975 points this season, and became the first player to book his place at the year-end event at the O2 Arena in November.

The Serb is is only the second player since 1990 to qualify for the year-end event before the French Open - Nadal was the first to achieve the feat in 2009.

Djokovic has been in imperious form this season and could overtake Rafael Nadal as world No. 1 if he reaches the final at Roland Garros.