Sunday 6 August 2017 14:53, UK
Andy Murray's time as men's world No 1 looks to be coming to an end, for now, but who will take over at the top?
Murray moved to the top of the rankings in November 2016 after a stunning second half of the season that saw him go 58-4 after losing to Novak Djokovic in the final of the Madrid Open.
But having won just one title this year and with a hip injury to overcome, Murray looks as though he could fall down the rankings. With Djokovic out injured for the rest of the year, who will take over at the summit? We look at the contenders, and what Murray could do to stay at the top...
A remarkable year for Federer looks as though it could get even better.
The 35-year-old has lost just two matches in 2017, won both Grand Slams he has participated in, and also secured titles in Miami, Indian Wells and Halle.
His win at Wimbledon saw him move to No 3 in the world, within 920 points of Rafael Nadal and 1,205 points of Murray.
While Murray has 5,460 points to defend for the rest of the season, Federer has none, having missed the hard court swing in 2016 due to injury. The last time the Swiss was No 1 in the world was November 2012, but a return to the top seems likely if he maintains his current form.
Federer's next stop is Montreal for the Rogers Cup, which starts on Monday, August 7 and is live on Sky Sports Action and Sky Sports Main Event.
He has not won the Rogers Cup since 2006, and will come up against a strong field. After Montreal it's off to Cincinnati, where Federer has had much more success, with seven tournament wins to his name.
"I think it's going to be a three or four-way race, or two-way race between me and Rafa Nadal," he said after winning Wimbledon. "I hope it's me and not Rafa because it means a lot to me to get back to number one."
Nadal has racked up most of his points this season on the clay courts, winning in Monte Carlo, Barcelona, Madrid and Roland Garros.
He could have moved to No 1 if he had played on the clay in Hamburg and made the final. However, he decided to take time off after his last-16 exit at Wimbledon and prepare for the hard-court season in the US.
Nadal did not play the Rogers Cup in Montreal last year but is featuring this season and, following Andy Murray's withdrawal, will move to No 1 if he makes the semi-finals. Nadal was last No 1 in June 2014.
He could also gain points in Cincinnati and the US Open, having lost in the last 16 of both tournaments in 2016.
However, the Spaniard has not won a hard-court title since 2014, when he was victorious in Doha.
He has also not gone deep at the US Open since 2013 when he won the tournament. He missed the 2014 edition and was then beaten in the third round in 2015 by Fabio Fognini and fourth round in 2016 by Lucas Pouille.
If Nadal can impress this year then perhaps a first US Open meeting with Federer could be on the cards. A meeting that could decide the No 1 ranking...?
It is not impossible for Murray to stay at No 1 in the world, but it looks a tough ask. He will not only need to regain full fitness, but he will need to reproduce his almost-perfect second half of 2016.
He could have surrendered top spot at Wimbledon if Djokovic had won the tournament, but now looks set to lose his grip in the coming months, especially after withdrawing from the Rogers Cup as he continues his recovery from a hip injury.
"I haven't played well enough this year to deserve to stay there for much longer," he acknowledged after losing in the Wimbledon quarter-finals.
"I don't think anyone has ever stayed at No 1 their whole career. It always comes to an end. That's fine. Obviously, I would rather be ranked No 1 than 2, 3 or 4. I go away now and try and find a way to get back there. Hopefully I can do that."
When he does return from injury, Murray faces a challenge to improve his position in 2017. He reached the final in Cincinnati last year, made the quarter-finals of the US Open, and won in Beijing, Shanghai, Vienna, Paris and London.
He might have missed his chance to challenge for No 1 at Wimbledon after losing in the first round, but Wawrinka could still be a contender this year, if he can recover from a knee injury that has troubled him recently.
Wawrinka will not play in Montreal or Cincinnati, saying in a statement he wants to be "on the safe side" with the injury even though he has been "battling hard" to return.
"I need to be 100 per cent confident before I resume competition that the injury that plagued me in Wimbledon has been resolved," he added.
The Swiss reached the semi-finals in Montreal last year and the last 16 in Cincinnati.
But his chances of making it to the top this year could come down to the US Open. Wawrinka is the defending champion in New York and an early exit would mean a significant loss of points.
It appears the only other realistic challengers for the top spot are Marin Cilic or Dominic Thiem, although both would need remarkable finishes to the year to have a chance.
Cilic especially would need to go on a strong run as he has points to defend in Cincinnati (winner in 2016), Tokyo (semis in 2016), Basel (winner in 2016) and Paris (semis in 2016).
Thiem has the opportunity to make up points as he had some early exits in the latter half of 2016, but he is 3,400 points behind Nadal.
While there are familiar faces at the top of the world rankings, it looks like there could be a few different faces at the ATP World Tour Finals in London. While Nadal and Federer are well clear at the top of the rankings, which are calculated only using points from the calendar year, there's not much separating those below.
The top eight qualify for the finals and Djokovic and Murray currently occupy the final two spots. Djokovic is set to drop out due to his injury, potentially opening the door for Grigor Dimitrov, Tomas Berdych or David Goffin to be in London.
Last year it was Djokovic and Murray going head-to-head in the final match of the year to decide the No 1 ranking, could the same happen again in 2017?
Who do you think will be the next world No 1? Have your say in the comments below or tweet @SkySportsTennis.
We will have the Masters 1000 series in Montreal and Cincinnati covered via our website skysports.com/tennis and you will also be able to watch all the action live on Sky Sports.
