Roger Federer will never reclaim the world number one men's tennis spot.
That is the view of former Swedish tennis ace Mats Wilander after Rafael Nadal ended Federer's 237-week run at the top of the ATP rankings last month.
Wilander believes - at this stage of his career - that the Swiss star is not interested in grinding out victories in small tournaments which are needed to regain the top spot.
Instead he thinks Federer will want to concentrate on winning Grand Slams and beating Nadal.
Wilander told German daily Sueddeutsche Zeitung on Saturday: "I do not believe Federer will be world number one again.
"That is due to the way the ATP rankings are calculated, because you have to be powerful week after week.
"If Federer wants to be world number one again, he will have to win lots of small tournaments and I don't believe that interests him.
"What he is interested in doing is winning the grand slam tournaments and beating Nadal," added the Swede, who won seven Grand Slam titles in his career.
Nadal officially became world number one on August 18 thanks to his victories over Federer in the French Open and Wimbledon.
The pair could now renew their rivalry in the US Open final at Flushing Meadows, where both are through to the semi-finals.
Defending champion Federer takes on Australian Open champion Novak Djokovic, while Nadal takes on British hope Andy Murray.
If the pair win through, Wilander, 44, believes the hard-court surface of the Arthur Ashe Stadium offers the Swiss star his best chance of beating clay-court king Nadal.
"It is on this surface that the play of Nadal is most readable," added Wilander.

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