Novak Djokovic will return to the top of the ATP rankings for the first-time since October, 2016 when the new rankings are released on Monday after current #1 Rafael Nadal withdrew before his first match against Fernando Verdasco in Paris. It is an outcome that had looked inevitable for the past few months, but it is a remarkable achievement for the Serbian all the same as he becomes the first man ever to rise to the top of the rankings tree having been ranked outside the top 20 in the same season.

Few would have predicted that Djokovic would make such a climb after watching him stumble in limp defeats to Taro Daniel in Indian Wells and Benoit Paire in Miami. But the clay court season, which saw him reunite with former coach Marian Vajda after an unsuccessful stint with Andre Agassi and Radek Stepanek, saw signs of progress. His impressive run to the semifinals in Rome was the highlight, although a loss to the unseeded Marco Cecchinato in the last eight at Roland Garros was a setback.

But it was one he used for motivation on the grass and the results were spectacular. After losing narrowly in the final at Queen’s to Marin Cilic, Djokovic cut a swathe through the Wimbledon draw en route to his fourth title at the All England Club and 13th Grand Slam overall. Djokovic was back to his best and he did not let off during the North American hard court swing, completing the Career Golden Masters by winning in Cincinnati before dominating in New York to lift his third US Open crown.

Nadal, meanwhile, was losing ground to his rival in the fight for the #1 ranking. Despite winning the title in Montreal, he failed to defend his US Open crown after a knee injury forced him to retire from his semifinal with Juan Martin del Potro. That same knee injury then kept him out of the Asian Swing, leaving him stuck on the sidelines as Djokovic won the title in Shanghai to all but guarantee his return to the top of the world rankings.

It was a return confirmed by Nadal’s withdrawal today and it leaves Djokovic in pole-position to finish the year as the world’s best, which would be the fifth time he has accomplished the feat. That being said, Nadal will surely hope to carry the fight on to the ATP Finals and the fans may well be treated to a battle-royale between two of the greatest of all time. He has not yet said whether his health will allow him to play, though. But for now at least, it is Djokovic in the ascendancy, a fact already established on the court and now apparent in the rankings as well.