Both Roger Federer (L) and Rafael Nadal were brought to tears during a ceremony to salute the career of the retiring Federer. Photo / Getty

Roger Federer has opened up on the iconic moment he held hands with Rafael Nadal during his emotional swan song at the Laver Cup last week.

The two tennis icons lost their doubles match for Team Europe against Team World’s Frances Tiafoe and Jack Sock, but there wasn’t a dry eye in London’s O2 Arena as the reality set in that Federer had played his last ever match.

Federer has enjoyed a storied rivalry with Spain’s Nadal over nearly two decades – together they have won 42 Grand Slam singles titles in a golden era for the men’s game.

The pair, who first met in 2004, played 40 times, including in nine Grand Slam finals, with Nadal holding a 24-16 winning record.

But they were on the same side of the net in a fitting farewell for Federer, who turned professional nearly a quarter of a century ago.

There were emotional scenes afterwards when Federer and Nadal started crying while sitting next to each other and the Swiss maestro instinctively reached out to hold Nadal’s hand.

A photo of the two tennis icons in tears quickly went viral around the world as Federer’s retirement begun to sink in.

In an interview with the New York Times, Federer said he had seen the photo of him holding hands with Nadal and described the heartwarming act as a “secret thank you” to the Spaniard.

“Well, I mean, it was a short moment,” the 41-year-old said.

“I think at one point, I was sobbing so hard, and I don’t know, everything was going through my mind about how happy I am to actually experience this moment right there with everybody.

“And I think that’s what was so beautiful about just sitting there, taking it all in while the music was playing, and the focus was maybe more on her (the singer Ellie Goulding). So, you almost forgot that you’re still being taken pictures of.

“I guess at one point, just because obviously I couldn’t speak and the music was there, I guess I just touched him, and I guess it’s maybe a secret thank you.