Rafa Nadal moment with Serena Williams sends tennis world into meltdown

The tennis world has reacted to a special moment between Rafa Nadal and Serena Williams only days out from the American icon's final grand slam tournament.

Williams announced the US Open would be her farewell tournament following an illustrious career spanning more than 20 years.

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The 23-time grand slam winner has been seen training hard ahead of her first round match and took to Arthur Ashe stadium again for a hit.

And as she finished, 22-time grand slam champion Nadal walked onto court.

The Spaniard was scheduled to practice after Williams.

And the pair greeted each other in what will be the last time the duo will play at the same grand slam on tour.

Fans were quick to praise the special moment - with a combined 45 grand slam between the duo - as two legendary athletes crossed paths.

Nadal also said hello to Aussie Rennae Stubbs, who has taken on an advisor role for Williams ahead of her final grand slam.

Rafa Nadal's praise for Serena Williams

Rafa Nadal recently praised Williams after the 40-year-old announced the US Open would be her final tournament.

"She is one of the greatest sports [people] of all time," he stated.

"I feel lucky to share a tour for a long period of time with her.

"Of course, from a selfish point of view, it's sad that she's leaving the tour but, on the other hand, we can't thank her enough for all the things that she did for our sport.

"I think she's an amazing inspiration for a lot of people around the world and I think she deserves to choose whatever works for her better at this stage of her life.

"So I wish her all the best. Hopefully, we can keep seeing her around the tour because I always believe that our sport, or the sport in general, is bigger and better when legends are around and she is a legend.

"Hopefully, we can enjoy her in a different way around the tour."

Williams is seeking a record-equalling 24th grand slam title to draw level with Margaret Court's all-time tally.

And in an attempt to finish on a fairytale, Williams has enlisted the help of Aussie tennis great Stubbs.

Stubbs - a four-time grand slam doubles winner - has taken on a role in her coaching team offering advice ahead of the tournament.

The Australian was again with Williams today after their training.

Nadal is heading into the US Open with only one match under his belt having lost to eventual champion Borna Coric at the Cincinnati Masters.

The Spaniard withdrew from the Canadian Open after suffering an abdominal tear at Wimbledon.

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