Roger Federer is odds-on to finish the year as world number one for a record-equalling sixth time.
Sky Bet offer 8/15 that the new Wimbledon champion, who turns 36 next month, will finish the 2017 season on top of the ATP rankings.
Were he to do so, Federer would become the oldest world number one in history – Andre Agassi, who was 33, is the current holder of that ‘honour’.
Federer has already won the Australian Open and Wimbledon this season, en route to racking up a 31-2 win-loss record. He has also missed match point in both encounters he has lost.
However, having skipped the claycourt season during which rival Rafael Nadal cleaned up, Federer currently trails the Spaniard in the 2017 points standings.
French Open winner Nadal – a 6/4 shot to finish as number one - has accumulated 7,095 points with Federer currently on 6,545.
However, the hardcourt season is about to begin with Federer historically stronger during this period of the year.
He is the 9/4 favourite for the US Open, which begins next month and has 2,000 points on offer to the winner.
There are also 1,000 points available at each of the remaining Masters tournaments – in Montreal, Cincinnati, Shanghai and Paris – while the winner of the season-ending ATP Finals will claim 1,500.
Both Federer and Nadal have already qualified for the elite eight-man event at London’s O2 Arena and there appears every chance the battle to be year-end number one will be decided during that week in November.
The Swiss is already the 9/4 favourite to win there with Nadal out at 11/2.
Sky Bet trader Chris Kennedy said: "Federer looks the man to beat in the race for number one with the major events left in the season being held in the North American hardcourt season followed by the European indoor swing.
"These playing surfaces looks to favour the game of the Swiss ace but Nadal has looked sharp on all surfaces this year and cannot be ruled out."
Federer has spent a record 302 weeks in his career as world number one. He was last in top spot in November 2012.
Nadal’s third spell as number one ended in July 2014. He has totalled 141 weeks in top spot.
With only 2,290 points earned in 2017 so far, current world number one Andy Murray is rated a 150/1 shot in the market.
Novak Djokovic is only slightly better off with 2,585. He can be backed at 100/1.
The world number one spot is decided by a rolling 12-month points system. By the end of the season that 12-month period mirrors the calendar year.
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Odds correct as of 1430 BST on 19/07/17.
