Is this the year when the next generation of men's tennis finally usurps the "Big Four"? It is a question that has been asked often over the past decade. At first glance, it might seem strange to suggest that the Big Four - the injury-ravaged Andy Murray aside - are about to be replaced. After all, the other three members, Roger Federer, Rafael Nadal and Novak Djokovic have hoovered up the past eight Grand Slams between them. The trio will be the top three seeds at the Australian Open, which begins on Monday, and are the bookies' favourites.
And yet there is increasing conviction among some of the tennis cognoscenti that 2019 will be a year of change. "There's certainly something in the air," said Boris Becker. That "something" can broadly be split into two categories: the credible emergence of younger talent and the reduced invincibility of the Big Four.
Starting with the former group, Becker is well placed to assess the strength of the leading youngsters. Becker won Wimbledon twice before his 19th birthday, and believes that in Alexander Zverev, 21, Karen Khachanov, 22, Stefanos Tsitsipas, 20 and Borna Coric, 22 there are young players ready to become Grand Slam champions.
"Zverev looks like the best of the rest. He is catching up, his victory at the ATP Finals, beating Federer and Djokovic back-to-back was huge, but equally Khachanov winning the Paris Masters, Tsitsipas' performances throughout the year, Coric's performances again. They're knocking at the door very loudly, and eventually it will blow open.
"There's certainly something in the air, that the young guys are going to break through at the Grand Slams - especially this year."