Novak Djokovic accidentally hit Roger Federer with the tennis ball during their Laver Cup doubles defeat in Chicago on Friday night.
Federer and Djokovic - who have a remarkable 34 Grand Slam titles between them - took a while to settle into the four-man format, the latter - on the back of his US Open triumph and 14th major title - accidentally hitting his partner with the ball in the third game.
The Serbian and Swiss both laughed off the incident to the amusement of the crowd and although they went on to win the first set, they eventually lost the match to Jack Sock and Kevin Anderson 6-7 (5-7) 6-3 (10-6).
Djokovic said "his heart stopped for like three seconds" as the pair spoke about the incident on the bench.
Click on the video above to see Djokovic's amazing reaction after catching Federer with the tennis ball and then watch their reaction below...
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