ATP Finals alternate Matteo Berrettini believes Novak Djokovic has 'a little less energy' than usual right now.
Djokovic has endured a very tough year from a mental standpoint, as he has had to deal with the ill-fated Adria Tour coronavirus outbreak, the fallout from his US Open disqualification, and the opposition to the PTPA.
And that, according to Berrettini, looks like it has understandably taken its toll on the world number one.
"The winner of the Finals? I can't tell," Berrettini told the Italian press. "There will certainly be two great semi-finals and then there will be a super final.
"Rafa is adapting to the indoor conditions. Djokovic has a little less energy [than usual] but he has only lost three matches this year and when the level rises he is always there.
"I see Medvedev [is playing] well but it is tough against Nadal. I have played with everyone here in London except Nadal. On free days he always trains with [Carlos] Moya."
Berrettini made his debut at the APT Finals last season, but a poor 2020 has seen his edged out this year by Andrey Rublev and Diego Schwartzman.
He, along with Denis Shapovalov are alternates, meaning they were available to step in should there be an injury to someone else, but he is happy that has not happened.
"Nobody got injured and I stayed on the bench, and that's only right.
"I would never have enjoyed the forfeit of one of the eight finalists."
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