There was total disbelief from fans, team-mates, captains, commentators and even the players themselves after one point between Alexander Zverev and John Isner during their Laver Cup clash.
At 2-2 0-30 on the American's serve in the opening set there was a truly bizarre point at the TD Garden in Boston which no one could quite understand, even after the replays.
Isner appeared to celebrate with a clenched fist after slamming what he clearly felt would be a forehand winner to Zverev's backhand side, only for the German to somehow get it back with a crazy volley on the lunge.
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Then perhaps thinking that the Olympic champion's effort was drifting out, Isner simply left the ball as it dropped in. Strangely, he did not even make a play at the ball despite being right next to it.
Indeed, he inexplicably just casually swatted the ball behind him after the double bounce while standing beside it.
Both players looked totally bewildered as the American suddenly realised, much to his confusion, that he had made a horrible misjudgement and actually lost the point.
Eurosport commentator Chris Bradnam reflected how everyone felt when he exclaimed, "What?! I can't believe he won that point!
Why did Isner stop?!
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Miles Maclagan, who joined Bradnam in the booth, added: "Did he think it came off the body of Zverev? It was nowhere near!"
Zverev went on to take the opening set on a tie-break with Team Europe totally dominant once more and on course for a fourth successive Laver Cup triumph.
Unfortunately, the courtside microphones did not manage to pick up Team World captain John McEnroe's reaction to Isner leaving the shot earlier in the set.
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You can watch the Laver Cup live on Eurosport 1, eurosport.co.uk and via the Eurosport app. Download the Eurosport app for iOS and Android now to get yourself all set for the action from Boston.
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