ATP Finals 2019: How can Rafael Nadal clinch the ATP year-end No.1 ranking?

Rafael Nadal reached his first Paris Masters semifinal in six years but had to withdraw from his semifinal against young-gun Denis Shapovalov, owing to an injury.

Novak Djokovic duly took advantage of the unexpected slice of good-fortune by overwhelming the young Canadian in the title match en route to clinching a record-extending 5th Paris Masters title, and 34th Masters 1000 crown.

Nadal, however, still holds most of the aces in his effort to clinch a 5th year-end World No.1 ranking at the season-ending 2019 ATP Finals.

Given that every win from the group stages guarantees 200 points, a win from the semifinal brings about 400 points and a win in the final hands the victor 500 points, the scenarios are aplenty for Nadal to clinch the top ranking at the end of the grand finale.

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#1 Nadal remains unbeaten throughout the round-robin stages and makes the final

Nadal would earn 1000 (200*3 + 400) points in this scenario. Combined with his 640 point head-start going into the season finale, the Spaniard would finish with 1640 points in his kitty, which would be an unassailable lead even if Djokovic wins all the matches he plays, including the finals.

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#2 Nadal loses one round-robin match and takes the title

This scenario would see Nadal earn 1300 points (200*2 + 400 + 500), for a net lead of 1940 points. If Djokovic wins his three group stage matches, the semifinal and loses the final, he will collect a total of 1000 points but will fall way short of Nadal.

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#3 Nadal loses two round-robin matches, qualifies for the semifinals and takes the title

In this case, Nadal would have 1100 points (200*1 + 400 + 500) for a net lead of 1740 points.

Notably, only two men in the history of the ATP Finals have endured two round-robin defeats and avoided a group-stage exit. Kei Nishikori (2016) and David Nalbandian (2006) qualified for the semifinals following two round-robin losses, but both men failed to reach the final.

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#4 Djokovic loses or doesn't make the semifinals

Djokovic can earn a maximum of 600 points by winning all of his three round-robin matches, but if the Serb loses in the semifinals, he will be unable to overhaul the 640-point lead enjoyed by Nadal in the race for the year-end World No.1.

Djokovic may also miss out on playing in the semifinals if he drops a match or two in round-robin stages. If two others, apart from the Serb win two round-robin matches, the Serb may miss out on the semifinals if he has the worst set win-loss mark or games won percentage.

In the event of a three-way tie for second place in the group, with one win apiece, Djokovic could miss out on a semifinal spot if he does not have the best sets win-loss mark or games won percentage.

Of course, if Djokovic does not win a round-robin match, which hasn't happened since the Serb's ATP Finals debut in 2007, Nadal would seal the year-end No.1 for a 5th time, without having to worry about his performance at the year-ending tournament.