Roger Federer has admitted that he is struggling with tiredness ahead of the ATP World Tour Finals in London.
The former world number one claimed the Paris Masters for the first time in his career on Sunday.
While the Swiss pro will attempt to defend his Tour Finals title from this weekend, he admits that he needs to shake off some fatigue.
"Right now I feel very tired, I'm not feeling great," ESPN quotes Federer as saying.
"The load is on my shoulders and I will probably be even more tired, but we will see how it goes."
Federer will join world number one Novak Djokovic, British hopeful Andy Murray, Tomas Berdych, Mardy Fish, Jo-Wilfried Tsonga and Spaniards David Ferrer and Rafeal Nadal at the O2 on Sunday.
