The Big Four have been dominating the game for longer than anyone believed possible, but nothing lasts forever. Rafael Nadal has been missing in action since September, Andy Murray is slowly recovering from injury and has confirmed that he will retire this year and – whisper it – even Roger Federer is starting to show signs of age. Does that mean that the Big Four will become the Big One and Novak Djokovik will have the stage to himself? Perhaps, but his defeat to the 21-year-old Alexander Zverev was hardly the best way to end the ATP season last November.
Opportunities for a new guard
Times are changing, and that doesn't just mean opportunities for youngsters like Zverev. Last week's screaming headline of Kei Nishikori wins Brisbane International and ends title drought shows that 2019 could be a moment for many of those who have languished in the shadow of the Big Four to get their moment in the sun.
If he had been around in any other era, Nishikori would almost certainly be a multiple Grand Slam winner by now. As it is, the likeable 29-year-old has the honour of being the only male Japanese player to enter the top five, something he achieved briefly in 2015. In a career that has already spanned 11 years, Nishikori has always looked like the real deal, yet has never quite managed to overcome the giants of his era.
The likes of Federer and Nadal have disproved the conventional wisdom from the Stefan Edberg and Pete Sampras years that a player will be well past his peak by the time he reaches his 30th birthday. This is a landmark that Nishikori will reach later this year, and his stunning start to the season is exactly what he needed to prove that his best might be yet to come.
Young guns to watch for
Nishikori, along with other top 10 players like Marin Cilic and Juan Martin del Potro will be keen to take the opportunity presented by a relaxation of the old guard, but these are all players in their 30s, too.
From the younger cohort, Zverev is, of course, a man going places, but also watch out for his fellow Russian Karen Khachanov as well as 20-year-old Stefanos Tsitsipas, who exploded up the rankings from 91 to 15 over the course of 2018. This coming season could be the most difficult to predict in years.