Alexander Zverev, Dominic Thiem and the Next Generation are coming fast, and only one giant obstacle stands between them and a major breakthrough at the French Open.

All of the 'Big Four' have now entered their 30s and shown signs of slowing down, albeit never at the same time.

Andy Murray and Novak Djokovic's dominance of 2016 has been replaced by the revivals of Roger Federer and Rafael Nadal this year.

But with his knee an ongoing concern, and Nadal's form looking set to make the king of clay unstoppable, Federer has opted to skip Roland Garros and focus on the grass and hard-court seasons.

A nine-time French Open champion, Nadal is 17-1 on clay this year. With Murray and Djokovic below their best, 'La Decima' would seem inevitable.

But the continued emergence of Zverev and Thiem, and the likes of David Goffin, gives the Next Gen a huge opportunity.

Zverev has clay-court titles in Munich and Rome – the latter including a final win over Djokovic – to his name in 2017 and the German has risen to 10th in the world rankings.

Like Nadal, Thiem has 17 wins on the surface this year, but suffered straight-sets losses to the Spanish great in finals in Barcelona and Madrid.

The talented Austrian did end Nadal's winning run, however, with an upset victory in their Rome quarter-final. A crushing defeat at the hands of Djokovic, who holds a 5-0 win-loss record over him, in the semi was worrying, but fatigue surely played a part.

The form of the likes of Thiem (17-4 on clay this year), Zverev (16-3) and Goffin (10-4) is in contrast to the likes of Murray (4-4), Djokovic (8-3) and Stan Wawrinka (4-3).

World number one Murray, coming off an incredible 2016, has struggled – particularly on clay – and his hopes of a first French Open crown appear slim.

Djokovic enjoyed a much-needed run to the final in Italy and the addition of Andre Agassi as coach for the year's second major continues the changes for the Serbian as he bids to recapture the form that started to slowly slide after he completed a career Grand Slam in France in 2016.

Wawrinka, the 2015 champion, is a man for the biggest occasions, but it will take a fair turnaround in form for a player who has a 4-3 win-loss record on clay this year.

It opens the door for players like Thiem, a semi-finalist at Roland Garros last year, and Zverev, who has never been beyond the third round of a grand slam, to make their charges.

Only the king – Nadal – appears to be standing in their way, but the Next Gen are coming, and coming fast.