“Zverev has given him trouble in the past. He’s just got an awkward game style and matches up well against Rafa, so this is going to be a big ask.

“But there’s a part of me that thinks if this is going to be his last French Open, to lose to Zverev might be a little more fitting than to lose to someone … ranked 80 or 90, which is possible.”

When prodded on the topic of retirement ahead of Roland-Garros, Nadal grinned.

“It’s a big, big chance that it’s going to be my last Roland-Garros,” said the 22-time grand slam champion.

“But if I have to tell you it’s 100 per cent my last Roland-Garros? Sorry, but I will not, because I cannot predict what’s going on.”

Nadal and Zverev have met on 10 occasions on the ATP circuit, with the Spanish maestro holding a 7-3 head-to-head edge.

Of the six times they’ve faced each other on clay, Nadal has won five times.

The veteran has also beaten Zverev the three most recent times they’ve squared off on any surface.

All of Rafael Nadal’s grand slam triumphs, in order

Masur hailed the “big four”, praising Nadal, Roger Federer, Novak Djokovic and Andy Murray.

“They’ve left the sport in a better place,” Masur said.

“Every time they played they gave a maximum effort, and you can be sure at times they were hurt, not feeling their best, there were things going on in their private lives, but they absolutely committed to the sport.

“They competed at every turn and Rafa was maybe the epitome of that. [He had] this outrageous, never-say-die attitude.

“He was a unique blend of endurance, speed and power.

“I’ve never seen anyone quite like it.”