Novak Djokovic was forced to retire from his semifinal match against Taylor Fritz at the Six Kings Slam in Riyadh after an exhausting opening set left him unable to continue.
According to Marca, the exhibition tournament, featuring several of the sport's top stars, was meant to be a lighthearted showcase before the close of the year.
Yet Djokovic, ever the competitor, treated it like any major contest. The 38-year-old battled through a punishing 75-minute first set that ended in a 7-4 tiebreak loss to Fritz.
Shortly after, he informed officials that he could not play on, appearing to struggle with a problem in his left leg.
When the match ended, Djokovic approached the net to shake hands with his opponent before addressing the crowd in Riyadh.
The Serb said, "I want to apologise to everybody, sorry guys, I'm sorry you couldn't see the second set. But credit to Taylor (laughs), I mean, we had some incredible games towards the end of that set, and it was one of the longest sets I've ever played, to be honest."
This latest physical setback comes after a stretch of fitness concerns in recent months. During the Shanghai Masters earlier in the fall, he appeared to roll his ankle in a win over Jaume Munar, later showing signs of discomfort in a semifinal defeat to eventual champion Valentin Vacherot.
The strain seemed to linger, and Djokovic admitted before arriving in Saudi Arabia that he was still managing "some issues" with his body.
