Nitto ATP Finals 2019: Rafael Nadal's chances of winning the title 

For the past few days, there was a big question mark looming over the health quotient of Rafael Nadal, after the Spaniard retired during the semifinals of the Paris Masters last week. Crowned as the World No.1, Nadal had been battling with several injury issues, and a particularly acute abdominal injury caused the 32-year-old to play safe by exiting the Bercy Open match against Denis Shapovalov.

With the pursuit of bagging a rare first London trophy on his mind, Rafa Nadal has finally consulted with his doctors and decided to make his bid at the O2 Arena, for the ninth time in his career.

There isn't much that the 19-time Grand Slam Champion has amiss from his trophy cabinet, yet somehow, the stars have never aligned for Nadal to win the ATP Finals. Nadal, who is steering ahead of Novak Djokovic on the rankings list by 640 points, has hopefully put his injury issues to rest because the competition is going to be fierce. For Nadal, 2019 has been yet another special year as he has come dangerously close to touching Federer's record 20 Grand Slams pedestal.

Right from the beginning of the year, Rafael Nadal has had a brilliant season on-court. For the first time in his career, Nadal raced to the finals of the Australian Open without having dropped a single set or being broken more than twice.

The story at the finals was a different one altogether with Novak Djokovic, playing a relentless match which saw Nadal losing in straight sets for the first time in any Grand Slam final. Despite the loss in the finals, which served as an indication for the tense Djokovic vs Nadal race ahead, Nadal went on to play in Mexico where he lost in the second round against Nick Kyrgios.

Injury issues have been constantly plaguing the Spaniard as he had to wait for the clay swing to finally turn things around for him. Rafael Nadal immersed himself in full force during the clay season.

The Spaniard typically made it to semifinals of the Monte Carlo Masters, then the finals at Barcelona, followed by another semifinal finish at Madrid and all of it was topped by a 9th title victory in Rome against Djokovic.

Among those who slew Nadal on his favoured surface at the various pre-French Open tournaments were Dominic Thiem and Stefanos Tsitsipas (both potential opponents in the London ATP Finals) as well as Fabio Fognini.

With the victory in Rome under his belt, Rafa Nadal cruised through the French Open and after a much-awaited clash with Roger Federer in the semifinals, Nadal went on to crown himself the champion for the 12th time. By doing that, Nadal surpassed Margaret Court's record of winning 11 Australian Open titles.

The grass court season wasn't the best outing for Nadal as he failed to get any title during that phase. His performance in Wimbledon was nothing out of the ordinary unless we take into consideration his match against Roger Federer, in the semifinals of the tournament.

A four-set match, it was an endearing trip down the lanes of nostalgia with Nadal and Federer giving each other their best shot. It was Federer's day as he defeated his arch-nemesis to go into the finals against Djokovic.

Nadal's tables turned again with the beginning of the hard court season as he quickly defended his first title on a court that was not clay at the Rogers Cup. It was an all-Nadal show at the Masters 1000 tournament where the Spaniard bypassed Federer on the list of having the most Masters match victories.

After the Rogers Cup, Nadal put his full attention into the US Open and unfurled ravishing form in the tournament. Playing breathlessly sensational quality of tennis, the Spaniard left no room for error in making it to the finals at Flushing Meadows.

Up against his Rogers Cup finalist foe, Daniil Medvedev, Nadal engaged in a five-set battle with the rising Russian star. The victory at the US Open, his fourth one so far, was a surreal achievement. With 19 gleaming Grand Slam titles to his credit, Nadal has all but established his dominance once again this year.

Coming into the ATP Finals this time, Rafael Nadal, who is secretly craving the season-ending title, has a lot at stake here. Drawn in the Andre Agassi group, alongside Medvedev, Tsitsipas and Zverev, Nadal will open his campaign against Zverev on Monday night.

With Novak Djokovic, a five-time former champion in London, breathing behind his neck, eager to topple Nadal from the World No.1 pedestal by winning the title, Nadal must put his guard up. The ATP Finals will act as a decider for the year-ending World No.1, for the first time since 2016, given the close margin competition that is ongoing.

With 1500 points up for grabs, Nadal must make his 9th appearance count and we should not be surprised if the Spaniard actually achieves this milestone by the end of this week and remain at the top spot, going into 2020.