Coco Gauff is headed to the Round of 16 at the China Open after defeating Xinran Sun, but the victory didn't come without controversy.

A challenge by Gauff drew backlash on social media, prompting the American star to respond with a lengthy explanation and declare, "I'm not a cheater."

Here's a look at what Gauff had to say and why her challenge stirred controversy.

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Coco Gauff responds to cheating allegations

Gauff appeared to have lost the opening set to Sun before raising her hand for a challenge due to a flickering light from one of the panels along the side of the court. While she appeared to raise her hand before the point was won by Sun, some accused her of simply challenging to keep her chances in the set alive.

Gauff explained Monday that she was simply following the rules, which allow players to challenge after the point. 

"We are told before the matches we are allowed to continue to finish play," Gauff said, adding, "My opponent is also free to do the same thing and ask for a replay and she would've have [sic] been completely in her right to do so."

@HHuotui https://t.co/ibmUEz84Qk

— Coco Gauff (@CocoGauff) October 5, 2026

Gauff explained that she initially saw the light flicker at the beginning of the point but wasn't sure what she saw and decided to challenge after it flickered again. 

Here's a look at the sequence.

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Coco Gauff controversial challenge

Gauff put her hand up to challenge mid-point, just before Sun hit the ball back to her for what would've decided the set.

@tmlfcc @slice_szn They didn’t show this on the broadcast review, coco put her hands up immediately after they flickered, so maybe she didn’t even see the earlier flickers https://t.co/8FBESLhw31

— ♥️ (@VenusGauff) October 5, 2026

Instead, Gauff's challenge was granted, and she went on to win the set before easily taking the second set and advancing.