Rafael Nadal has just won his 11th Roland Garros title at the age of 32.
Roger Federer, at the age of 36, is favourite to win this year's Wimbledon.
These two players have won all the Grand Slam titles between them since Melbourne last year and appear to be unbeatable.
Who might be future contenders for those Slam titles?
Most consider Alexander Zverev and Dominic Thiem to be the ones knocking on the door. They have each taken sets off Nadal on clay this year and are numbers two and seven respectively in the ATP world rankings.
However, at Roland Garros, Nadal beat Thiem in three straight sets and was relatively untroubled. It's a far greater task to beat Nadal over the best of five sets on clay at Roland Garros than to take a set in a best of three at a more minor tournament.
Andre Agassi, though, recently came up with two other predictions, both Americans; Frances Tiafoe and Reilly Opelka.
Both 20-year-olds, Tiafoe stands at 63 in the world rankings, whilst Opelka at 153.
Tiafoe has had some great scalps against top players which have included Juan Martin del Potro, Denis Shapovalov and Hyeon Chung, and won his first ATP title on hard courts at Delray Beach earlier this year, all great indicators for the future.
Even Roger Federer has sung this young player's praises.
Opelka put his stamp on the game earlier this year at the Australian Open in Melbourne, taking 11th seeded David Goffin to five sets and also looks to have a bright future. The main reason Agassi picked him as a future champion, however, is his height.
He stands at an almighty seven feet, taller even than the current number ten, 6'10" American John Isner, which gives a huge advantage when it comes to service power. Isner rarely gets his service broken for this very reason and that puts enormous pressure on the opponent.
The last time a US player won a men’s Grand Slam was back in 2003 when Andy Roddick won the US Open.
Perhaps one of those two youngsters will create a resurgence in American tennis and even produce a Grand Slam title.
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