Tennis Players Protest ELS Calls During Madrid Open Clay Matches

Alexander Zverev sparked controversy at the Madrid Open after challenging an electronic line call during a clay match against Davidovich Fokina.

Tennis star Alexander Zverev has reignited the debate around electronic line-calling systems (ELS) after a controversial point during his Madrid Open match on clay against Spain’s Alejandro Davidovich Fokina, as first reported by The New York Times.

Zverev observed the backhand which barely touched the edge of the court while the automated system failed to make a call so the point counted as in. He immediately asked chair umpire Mohamed Lahyani to come down and inspect the ball mark left on the clay. “The machine is not working. Look at this mark … Don’t overrule it, please come down,” Zverev said, as reported by The Times.

Lahyani refused, explaining that under the current system, once the ELS makes a call, the physical ball mark is no longer used. The Times reports that Zverev, frustrated, took out his phone to take a picture of the spot which he later posted on Instagram. He received a code violation for this action, the same penalty that Aryna Sabalenka received days earlier in Stuttgart.

On clay, balls leave visible marks, traditionally considered the most reliable way to judge a shot. However, with the rise of ELS, human line judges are being replaced.

Systems like Hawk-Eye now use multiple cameras and predictive technology to decide whether a ball is in or out, with claimed accuracy down to three millimeters. But even this can be affected by court conditions, such as how dry or thick the clay is, as noted by The Times.

While Hawk-Eye says its system is ready for clay, some players aren’t convinced. Victoria Azarenka and Eva Lys also posted photos questioning calls made during the Madrid Open. Arthur Fils, after disagreeing with several points, even called for a return to line judges.

This ball in or out? pic.twitter.com/Y1dNViuO5K

— victoria azarenka (@vika7) April 25, 2025

ELC said its in… it was a wide serve. Thoughts ? 😀😀😀😀😀😀😀😀 pic.twitter.com/DIJAVemGue

— Eva Lys (@evalys_) April 25, 2025

“Clay is a very different surface — probably the most difficult surface to work on,” said ATP supervisor Cedric Mourier, noting how reading clay marks can be subjective, as reported by The Verge.

Despite the drama, Zverev went on to win the match in a close 2-6, 7-6(3), 7-6(0) victory. He now moves forward to face either Francisco Comesana or Francisco Cerundolo.