Can you spot why this Wimbledon photo sent fans wild?

It looks like nothing more than an ordinary photo of Rafael Nadal tuning up for the second week of Wimbledon with an off-day practice session.

But a closer examination reveals a rare event that made Middle Sunday at the All England Club that little bit more special.

The world No.1 Nadal is on the court closest to the camera.

To his left? None other than Novak Djokovic.

And one court over on the opposite end? Yep, Roger Federer.

Thirteen Wimbledon championships between them and 49 grand slam titles overall, it was quite the historic training run.

Tennis fans took notice:

All three players were warming up for ‘Manic Monday’, when all fourth-round matches in the men’s and women’s draws will take place after Sunday’s rest day.

Federer is up first, at 1pm local time on Centre Court, against Adrian Mannarino while Nadal will close the day’s play inside the 15,000-seat stadium against Jiri Vesely.

Djokovic, seeded 12th following time off with injury, will play Karen Khachanov last on the 11,000-seat No.1 Court.

Nadal and Djokovic could face off in the semi-finals, while Federer is aiming to get out of the top half of the draw to reach a 12th final at the All England Club.