According to IrishTimes.com, this is the first year since 2002 Federer has not made a slam final and has drifted in the world rankings to seventh.
Djokovic, who came from a set down to beat Federer in the semi-finals of the Paris Masters in Bercy on Saturday, was moved to comment with circumspection yesterday, the report said.
He said that from his point of view, Federer had not been moving as well this year as he did the year before, and that is one of the reasons why he did not have as much success this year.
However, the Serb said that the Swiss ace is never to be underestimated as long as he plays tennis since he has an incredible quality in his game.
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