The battle for supremacy in the tennis world between the Big Three and the GenNext of players has been growing with intensity over the past couple of years. The latter group has been closing the gap gradually by winning major tournaments and rising up the rankings.

But when it comes to the Grand Slams and the top rankings the Big Three still hold sway. So overall there was little change in the script when the 2019 season ended with the conclusion of the ATP Tour finals in London on Sunday.

It however could not be overlooked that the gap is progressively getting closer and this was symbolized by events in London when only one among the Big Three Roger Federer qualified from the group stage for the semifinals and the title clash was between two prominent members of the GenNext Dominic Thiem and Stefanos Tsitsipas.

And the latter confirmed his meteoric rise into the highest echelon of men's tennis by battling back to beat Thiem 6-7, 6-2, 7-6. It was only the third time since 2002 that none of the Big Three reached the final and while it need not signal a changing of the guard as yet, there was a momentum shift for the GenNext. It is also important to recall that Alexander Zverev another leading member of the next generation won the ATP Tour finals last year.

Rafael Nadal deservingly took over from Novak Djokovic as the No 1. After all the Spaniard won the French Open and the US Open, was runner-up at the Australian Open and semifinalist at Wimbledon. At 33 Nadal was the oldest player to finish the year as No 1. Djokovic who triumphed at the Australian Open and Wimbledon finished the year well ahead of third ranked Federer.

But the next four rankings continue to be occupied by Daniil Medvedev, Thiem, Tsitsipas and Zverev with only the positions changing during the year making it clear that the quartet is still hot on the heels of the Big Three.

Could 2020 finally see a change of guard? It could and the chief reason for believing this is Tsitsipas. When the 21-year-old Greek was crowned champion on Sunday it felt like a watershed moment. And Tsitsipas is confidence personified off court as well as on.

"I believe I'm really close on being crowned a Grand Slam champion. I know these are strong words that I say, but I do feel like I belong to be there," he boldly claimed after getting the better of Thiem. No young star has shone more brightly on the ATP Tour in the last couple of years than the prodigiously gifted Greek.

There have been false dawns before of course. Zverev, like Tsitsipas, was also 21 last year when he beat Djokovic to win the season-ender. But Zverev could not back it up in this year's Grand Slam events. Tsitsipas however is different. Ever since he won the GenNext ATP final last year he has emerged as the leader of the young generation and the front runner to take over from the Big Three.

For his part Thiem beaten in successive French Open finals by Nadal, also believes next year could herald a new Grand Slam champion."I think that for sure we can do it next year. We are all playing great tennis," he said. "Zverev, Tsitsipas, me and some other guys. I'm pretty sure that we're going to see a new and young Grand Slam champion next year."

Not to be left out Zverev too has expressed the view that he hopes to be among those to end the reign of the Big Three who have won the last 12 Grand Slams between them besides finishing the year as top three in the rankings for the third season in a row. “I think next year will bring a new Grand Slam champion because the young guys are playing incredible tennis,’’ he says.

All this after conceding that the record of the quartet at Grand Slams overall is pretty modest. Thiem has been a finalist at the French Open in 2018 and again this year while Medvedev lost in the US Open title clash this year to Nadal. The best for Tsitsipas is a semifinal berth at the Australian Open this year while Zverev’s best is a quarterfinal spot at the French Open in 2018 and this year.

Despite this Messrs Federer, Djokovic and Nadal will be having an anxious glance over their shoulders when the new season gets underway. Events in London revealed a new fearlessness in the generation of 20 somethings expected to fill the void when they call it a day. As former world No 1 Boris Becker succinctly put it “The question to be asked is where is the road going after Djokovic, Federer and Nadal and after this week I think we are in safe hands.’’

However whether The Big Three who have won 55 Grand Slam singles titles between them will be ready to abdicate is a moot point. All in all the stage is set for a most intriguing season in 2020.