Tuesday 12 September 2017 15:59, UK
With Roger Federer and Rafael Nadal booked, and regulars Novak Djokovic, Stan Wawrinka and Kei Nishikori out through injury, we analyse the form of the top eight ATP players chasing a spot at the season-ending World Tour Finals in London.
The O2 in London will once again play host to the top eight players in the world rankings with world No 1 Andy Murray hoping to defend his crown later this year.
With Nishikori joining Djokovic and Wawrinka in missing the rest of the season through injury, we have already lost three names who have played at each of the last three renewals of the season finale.
With Federer and Nadal back to their irrepressible best in 2017, we will have two legends of the game making their return having missed the showpiece last year.
However despite Federer and Nadal claiming the Grand Slams, new names have begun to emerge with Alexander Zverev claiming two Masters titles and Grigor Dimitrov picking up his first with victory in Cincinnati on Sunday.
It means we are in for an exciting battle over the final months of the season and we will be tracking the standings in the Race to London once they are updated.
Grigor Dimitrov - The brilliant Bulgarian claimed the biggest title of his career at the Western & Southern Open to continue his fine court season. More of the same in New York and he will get close to securing a London debut. His win in Ohio took him up to fifth in the race as well as ninth in the world rankings.
Nick Kyrgios - The Cincinnati final was a disappointment, but he took Nadal in straight sets to get there and showed admirable, and not unexpected, focus to turn around his match with Ivo Karlovic. There is no doubt Kyrgios is box office and his run to the final took him up nine places, only 385 points behind Sam Querrey in the current final spot.
Kei Nishikori - The niggling injuries that have dogged the world No 10 for the past couple of years took their toll when Nishikori withdrew from the US Open, and indeed the rest of the season with a wrist problem that ended his Cincinnati hopes. In truth he was always an outsider for a place in London but he will now miss out for the first time since 2013.
Andy Murray - The defending champion and now world No 2 has had his own injury problems. He has been battling a hip injury for some time and Dimitrov's win means he is in a vulnerable-looking ninth spot - if everyone was fit he would currently not qualify.
Nadal lost to Kyrgios in Cincinnati after a thrilling last-16 defeat to 18-year-old Canadian Denis Shapovalov in Montreal but he has reclaimed the No 1 ranking for the first time since 2014 on the back of his fine season.
Amazingly Nadal has never won the season-end, twice a runner-up it is perhaps the only thing missing from his bursting CV and he has confirmed his place with seven finals and four titles this year, including a 10th French Open.
Federer took the week off in Cincinnati to prepare for the US Open. It handed Nadal the No 1 ranking but Federer is defending virtually no points, having taken the second half of last season off.
With the Australian Open and Wimbledon titles safely tucked away, the 19-time Grand Slam champion will have his sights fixed on the magical number 20 at Flushing Meadow to go with his five titles won already this year.
Federer has six World Tour Finals titles but none since 2011.
The 20-year-old German is enjoying a fantastic period of form which has seen him claim the two biggest titles of his career and chalk up a career-best run at a major.
Having beaten Djokovic at the Rome Masters, he followed up by beating Federer to the the crown in Montreal to claim a fifth title of the year - the same as Federer and an ATP-leading tally for the year.
The German is widely regarded as the sport's next big thing and has already booked his place at the NextGen finals, a debut in London is not too far away either.
The Austrian is going through a sticky patch at the moment, not too dissimilar to last year when he roared out of the traps but suffered over the second half of the season.
The 23-year-old, who has played in 20 tournaments this season, appears to enjoy most of his success on the clay courts but at fourth in the race he is well-placed to follow last season's O2 debut.
Dimitrov has enjoyed a successful 2017 campaign culminating in the biggest title of his career - and a perhaps long overdue Masters series title.
Victory over Kyrgios in Cincinnati saw him claim a third title of the year and climb back into the world's top 10. With Stan Wawrinka injured, he sits fifth in the Race to London and looks on course for a debut at the season-end spectacular.
The former Cincinnati Masters defending champion was ruled out through an abductor injury and has still not featured since his run to the Wimbledon final.
As a 2014 US Open champion he will be a danger in NYC if he is fit and he could do with the points. Cilic will hope to be back to full fitness in time for the final Grand Slam of the campaign but will be without much-needed match practice.
Murray, the three-time Grand Slam champion, has not featured on the ATP Tour since suffering a five-set quarter-final defeat to Sam Querrey at Wimbledon.
Having lost his No 1 ranking, the Scot seems certain to head to the US Open but doubts over fitness remain in a season where he has one just one title and not reached a final since February.
His blistering 2016 ended with a staggering run across the final months of the season and a first victory at the World Tour Finals, something similar, if he is fit, may be needed to make his return to London.
The American No 2 is the highest place American in the race and holds the final qualification spot at the moment after a year which saw him end Murray's reign as Wimbledon champion and reach the semi-final of a Grand Slam for the first time.
However the big-serving 29-year-old has had a mixed hard-court season with early exits in both Montreal and Cincinnati. With a host of names queuing up behind him he is now in the position of being chased for that final spot and the season reaches it's conclusion.
Most of the contenders for the World Tour Finals will take a week off before heading to New York while some players further down the rankings will feature at the Winston-Salem Open, an ATP World Tour 250 event in North Carolina.
The US Open, the final Grand Slam of the year, at Flushing Meadows then awaits with massive ranking points up for grabs as Wawrinka watches on from home as the defending champion.
Sky Sports Tennis will have all the action from the US Open covered via our website www.skysports.com/tennis with our live blogs and updates through the fortnight as the final major of the year reaches its thrilling climax.
On the move? Head to our app for mobile devices and iPad, or follow our Twitter account @SkySportsTennis to join in the conversation. Who will win the US Open titles this year? Have your say...
We will also have coverage of the World Tour Finals in November with every match live on Sky Sports.
