:Defending ATP Finals champion Novak Djokovic has pulled out of the season-ending event through injury, he said on Tuesday.The record 24-times Grand Slam champion's absence means that Norway's Casper Ruud, Australian Alex de Minaur and Russian Andrey Rublev are all guaranteed to qualify for the eight-man even

Serb sits sixth in the ATP's annual rankings to determine the 8 competitors at the Finals

Novak Djokovic defeated Italy's Jannik Sinner in the ATP Finals last year. He has won the finals a record number of seven times. However, the Serbian great will not be able to defend his title this year as he has pulled out of it.