Coco Gauff's run in the women's singles tournament in Paris came to a crashing halt Tuesday following a last-minute call reversal in her match against Croatia's Donna Vekic.

Toward the end of the second set — with Gauff down 2-3, 30-40 — Vekic returned a forehand shot that was ruled out by a line judge as Gauff was striking the ball. Because of the call, which typically ends a point, Gauff didn't finish her stroke properly, resulting in the ball hitting the net. After Gauff made contact, the chair umpire called for a correction to the out call. The correction ruled Vekic’s shot to be in and Gauff’s return shot a fault. The result put Vekic up a break.

Gauff immediately disputed the point with the chair umpire. 

“You called the ball out before I even hit the ball,” the 20-year old emphatically told the ref. 

“That doesn’t matter,” the chair umpire responded. 

After a short time, International Tennis Federation tournament referee Clare Wood came on court, causing Gauff to change the target of her challenges. 

“It always happens to me on this court,” Gauff noted as tears streamed down her face. “I feel like I’ve been cheated on constantly. I hope one day the game becomes fair because it’s not."

Though the crowd seemed to be on Gauff's side, hurling criticisms at Vekic as the two returned to play, the American was unable to regain the composure with which she began the tournament, eventually losing the second set.

Here's a breakdown of what happened...

When the line judge called Vekic's ball "out", it would normally signify that Vekic's shot landed outside of the tennis court and was, therefore, a fault. In normal circumstances, the rally would end and the point would be awarded to Gauff. 

But the chair umpire quickly overruled the line umpire's "out" call, and shouted, "Correction." Thus, Vekic's shot that was previously called out was still considered in play, and Gauff's return was considered a fault. As a result, Vekic won the rally and point.

Section D of the ITF handbook states that, in the event that a line umpire makes a "clear mistake" in calling a play, a chair umpire may overrule the call if the overrule is made "promptly" after the mistake and the overrule follows other ITF procedures outlined in the handbook. 

This rule would validate the overrule made following Gauff's hit.

A line umpire is responsible for calling whether or not a ball bounces out of the court during match play, signifying a fault. 

A chair umpire manages and oversees a match's administration and organization. 

The ITF Paris Olympic Games official Duties for Officials guide outlines some of the responsibilities of the chair umpire, including:

• executing the pre-match coin toss
• keeping match time, time to serve, time between changeovers
• announcing the score after each point
• ensure that the rules are observed by the players and all on-court officials

Ultimately, in a tennis match, there is a hierarchy to the officials. The line judges report to the chair umpire, and the chair umpire oversees and manages the line umpires.

A video review in tennis is a relatively new system that is currently used in the U.S. Open and allows umpires to replay a point to review whether a correct official call was made, similar to a replay in baseball. As of now, only the U.S. Open uses this system in its tournament. 

The Australian Open and Wimbledon use an electronic line calling system. 

The French Open is the only Grand Slam that still entirely relies on line judges to make calls.

In Gauff's 2024 French Open semifinal match against Iga Swiatek, she also endured a call correction debate. 

In the second set, Swiatek hit a serve that was called out. As the ball was being called out, Gauff went to strike it and the timing of the call coinciding with Gauff's hit, and Gauff returned the serve out. 

Chair umpire Aurélie Tourte’s reversed the out call against Swiatek and awarded the serve point to the Polish powerhouse. Gauff argued that it was unfair because the out call impacted her stroke. 

“At this point, it’s almost ridiculous that we don’t have [video review],” Gauff told the press after the match. “There are so many decisions that are made, and it sucks as a player to go back or [watch] online, and you see that you were completely right. And it’s, like: What does that give you in that moment?”

Coco Gauff got into a similar argument with a chair umpire in the third round of the 2024 Dubai Duty Free Tennis Championships in February. 

Again in the second set, Gauff was on service, but this time with a 4-2 lead. On her second serve, launched at deuce, the attending line umpire called the attempt out after her opponent, Czechia's Karolina Pliskova, returned the serve. Gauff successfully challenged the call, but upon being asked to replay the point, she initiated an argument that lasted for five minutes, going so far as to ask to speak to the tournament supervisor.

"You called it out after she hit it," Gauff insisted. "Can you not cut me off for two seconds?"

Gauff returned to the court following the incident and won the match 2-6, 6-4, 6-3, thus advancing to the quarterfinals.

Coco Gauff is also competing in both the women's doubles and mixed doubles tournaments with Jessica Pegula and Taylor Fritz, respectively.