On Monday, Rafael Nadal, the current number one tennis star in the world, posted a video on Twitter thanking his fans for their support throughout the memorable year.The Spaniard said: "I just want to say thank you very much to all of you for your support. It’s been a very good year and today is special, going back to number one."His words come shortly after the 31-year-old replaces Andy Murray as the sport's number one.This sees Nadal return to the top position after a three-year hiatus at a lower ranking.It's been quite a good year for Nadal.In January, he made it to the final of the Australian Open, losing to Roger Federer. Then, in August, Nadal won his 10th title at the French Open.His words come ahead of the August 28 US Open in Flushing Meadows, New York.Nadal might have something of a clear run at the final Grand Slam of the year.Andy Murray, who Nadal officially dethroned on Monday, is suffering from a longstanding and worsening hip problem that may stop him competing.Novak Djokovic, currently ranked 5th in the world, will not compete for the rest of the season while he rehabs an elbow injury sustained during the Wimbledon quarter-final match against Tomas Berdych.In the run up to the US Open, one prospective challenger to Nadal is Roger Federer. Federer, who is now 36, could surprise many, not least himself, with a win at Flushing Meadows. The Swiss player has already won two majors in 2017.You can watch Nadal's video message to his fans below.

It's not clear to anyone that this will happen, least of all Federer himself, who recently told CNN Sport: "That would be a joke, if I won three slams this year out of nowhere.

"At some stage I almost feel like I have to be realistic...I’m not sure I can win three slams in one year. Winning two is already pretty crazy and plenty good enough for me."

Paddy Power begs to differ. Federer, at 6/4, is the favourite ahead of Nadal at 5/2.