There have been clear signs in world tennis the last couple of years that several young challengers have emerged who may finally take over from the old guard of Novak Djokovic, Roger Federer and Rafael Nadal. But despite the rise in the number of such contenders, the Big Three have continued to dominate both the rankings and the Grand Slams.

This year too it was pretty much the same with Federer winning the Australian Open, Nadal all too predictably the French Open and Djokovic the US Open and Wimbledon. The trio finished once more as the top three players in the ATP rankings.

However, at year's end there occurred an event to indicate that 2019 may well be the year their dominance comes to an end. Yes, there is no denying that Alexander Zverev winning the season ending ATP finals in London is a moment the tennis world has been waiting for. The 21-year-old German, acknowledged as the leader of the next generation of players which includes the likes of Juan Martin del Potro, Marin Cilic, Kevin Anderson, Joe Isner, Dominic Thiem and Kei Nishikori, finally lived up to his reputation.

Zverev's immense potential has been on view for some time, even with his mediocre Grand Slam results, his best being a quarterfinal entry into the French Open this year. He has never progressed beyond the fourth round at Wimbledon and was eliminated in the third round at the Australian Open and French Open. However, he won three Masters 1000 titles and has risen to No 3 in the world rankings.

And yes, he has wins over Djokovic and Federer. To beat both these players in back to back matches (semifinal and final) in one of the biggest tournaments on the circuit indicates he could well be the next big thing in world tennis. As Boris Becker, the last German to win the ATP finals in 1995, wrote in his column, 'The world saw a new superstar in tennis arrive on Sunday.'

Few will disagree with this view. Zverev, who is coached by Ivan Lendl ends 2018 ranked fourth, and there is every reason to believe that a year later he will be ranked even higher.

Djokovic had defeated Zverev 6-4, 6-1 in their round robin a few days before and was on a hot streak coming into the final, not having been broken even once in the tournament, facing only two break points and winning all 36 service games, but Zverev wrecked his numbers, breaking him four times in the match on the way to an emphatic 6-4, 6-3 victory.

The top seed from Serbia, ten years older than his opponent, came into the title clash looking to equal Federer’s record of six ATP Tour final wins, but that ambition will have to wait now.

While Zverev's emergence among the pack of young contenders was perhaps the single most significant happening of the year, the player of the season was still Djokovic. It is not just the fact that he ended the year as the No 1, or that he won two of the four Grand Slam events, but the manner in which he came back from injury and an indifferent start to the season that marked him out as one of the gamest triers in the history of the sport.

For someone who was ranked out of the top 20 midway through the year to end 2018 as the top ranked player signifies guts and fighting qualities of the highest order. Zverev himself paid tribute to Djokovic after the final in London, saying 'we have never have seen the kind of tennis he has played in the last few months when he barely lost a match.' Indeed Djokovic who had slipped to an unaccustomed low of 22nd in the rankings lost just three matches since the beginning of Wimbledon as he charged back up the rankings right to the very top.

Nadal and Federer maintained their exalted status despite an up and down year, finishing at No 2 and No 3 respectively, making it clear they will still be around fighting for the top spot next year, and bidding to keep the GenNext of players at bay.

But it won't be easy, for besides the players already mentioned two other young players made rapid strides this year: 20-year-old Stefanos Tsitsipas of Greece, who won the Next Gen ATP title, and 22-year-old Karen Khachanov of Russia, who served notice of his rise by winning the Paris Masters. On the way he defeated four top ten players in a row – Isner, Thiem, Zverev and Djokovic – a tremendous feat. By year end Khachanov was ranked No 11 and Tsitsipas No 15 after being nowhere in the picture at the start of 2018.