A flicker of stadium lighting in Beijing has turned into something far bigger than a tennis dispute. During her fourth-round win over 16-year-old Sun Xinran, Coco Gauff raised her hand to pause play, saying the advertising boards behind the court were distracting her. Sun believed she had already struck a winner. The crowd booed, the umpire ordered the point replayed, and Gauff won it anyway, closing out the match 7-5, 6-1.

What followed online, however, had nothing to do with the rules of tennis. Gauff said she was hit with an "insane" wave of racist messages after the incident, and felt compelled to defend herself publicly. "I'm not a cheater or a thief," she wrote, insisting she had challenged the point before Sun's shot had even landed, when the lights flickered a second time. The Women's Tennis Association said it was "appalled" by the abuse directed at her and was in direct contact to offer support, a reminder that even routine officiating moments can detonate into something uglier when race and nationality are involved.

By Wednesday, the toll was visible on court. Gauff, normally formidable in China, lost 6-3, 6-3 to Belgium's Elise Mertens, leaking eight double faults and 34 unforced errors along the way. "It has been kind of draining, I'm not going to lie," she admitted afterwards. Mid-match, she reportedly told her team she had no energy and felt close to fainting.