In the second game of the fifth set, home favorite Herbert asked umpire Timo Janzen to review a ball mark on the clay court, which he believed indicated Sonego's shot was out. Janzen descended to inspect the mark but confirmed the ball was in. This decision immediately ignited Herbert's anger.

Controversy between Herbert and the umpire during their Roland Garros first round match on 25/5.

Herbert reacted fiercely, accusing the umpire of misreading the ball mark. The 35-year-old player even declared he would never speak to the umpire again if he did not receive an apology.

"You saw the wrong ball mark", Herbert said angrily to the umpire during the match on 25/5. "No! Look into my eyes. You will see the ball was out. And if you don't apologize after this, I will never speak to you again. It's unbelievable".

The French crowd, predictably, sided with Herbert, creating a tense atmosphere on the court. Despite the heated exchange, Sonego maintained his focus, breaking Herbert's serve to take a 2-0 lead in the deciding set. The Italian player ultimately closed out the match with a 7-6, 5-7, 6-2, 1-6, 6-4 victory after over four hours of play.

Herbert during his match against Sonego on Simone Mathieu court, Roland Garros complex, Paris, France on 25/5. Photo: SIPA

The controversial incident in the recent match once again made Roland Garros a topic of discussion, as the clay court Grand Slam insists on not using electronic line calling technology, opting instead for traditional line judges.

Roland Garros organizers have for many years defended their stance, arguing that ball marks on clay courts are clear enough for direct umpire inspection. However, many players have called for the tournament to adopt technology consistent with the rest of the ATP Tour, aiming to avoid controversial decisions in major matches.

Clay courts are significantly affected by environmental conditions, as well as the distribution of red brick dust across different areas of the playing surface. The quality and characteristics of the court surface also vary continuously as these conditions change after each slide and movement by a player. A ball mark that appears to be in can sometimes display a mark outside the line. Conversely, a ball that is out can occasionally leave a mark as if it were still on the line.

This year's Roland Garros main draw began on 24/5. The men's singles final is scheduled for 7/6. The defending men's singles champion is Carlos Alcaraz, and the women's singles champion is Coco Gauff.

Vy Anh