Players on clay are increasingly clashing with electronic line calling when ball marks appear “proof” of an out call. Here’s why it happens and what it could change.
Tennis has always been a sport of split-second judgment—but on red clay, the new battle is over what “proof” even means.
At the 2025 Madrid Open. Iga Świątek won a point over Alex Eala after electronic line calling (ELC) said a serve was in. even though a visible ball mark on the clay suggested it was out.. Eala’s frustration wasn’t mainly about losing the match; it was about being asked to distrust something physical and right in front of her.
This isn’t an isolated moment.. One year later in Madrid. Elena Rybakina faced a similar scene: a shot appeared clearly out based on the ball mark. yet the system’s decision went the other way.. Rybakina’s reaction was blunt and emotional. reflecting what’s becoming a familiar pattern for players on clay—where their eyes and the technology can both claim they’re correct.
The heart of the dispute is simple: clay carries memory.. When a tennis ball strikes. it compresses and disrupts the red dirt. leaving traces that can look dramatic to the naked eye.. Electronic line calling is designed to remove that uncertainty by determining the bounce with high-tech precision.. But clay doesn’t behave like grass or hard courts, where the ball’s contact is harder to see.. On clay. the ground can produce marks that seem to “tell a story”—even when that story doesn’t match the system’s logic.
That clash has grown as ELC has spread.. As of 2026. Hawk-Eye ELC is used at three of the four Grand Slams and across men’s and women’s top-tier tour events above a certain threshold. including the Madrid Open.. The Australian Open adopted it in 2021, the U.S.. Open in 2022, and Wimbledon followed last year.. The French Open remains the outlier, continuing to rely on ball marks left in the clay alongside human line judging.
The social media era has also changed how quickly controversy travels.. When players believe technology is wrong, they no longer just protest—they often document.. In Madrid. Alexander Zverev reportedly used a phone to capture a trace he believed proved a call should have gone the other way.. Aryna Sabalenka faced her own moment in Stuttgart. where she questioned an out call; the wider point is that these incidents now become instantly replayable narratives. not just private disputes in the heat of a match.
Why does the technology sometimes disagree with the mark a player can see?. Clay’s “live” quality plays a role.. The court can vary depending on how much red brick dust is present in different areas. what the weather does to surface conditions. and how a ball lands and travels.. A compressed impact can leave shapes and patterns that look definitive—yet those patterns don’t always map cleanly to the exact bounce location that officiating systems try to measure.
It’s also worth understanding what “margin of error” means in practice.. Systems like Hawk-Eye ELC are designed to handle tiny differences—on the order of millimeters—when deciding whether a ball is in or out.. But when a ball mark is visible to the human eye. it can feel less like millimeters and more like “obvious evidence.” That mismatch between scientific tolerance and human perception is where anger is born.
The deeper issue is psychological, not mechanical.. Tennis asks players to recalibrate their instincts—sometimes against the most convincing cue they’ve always trusted.. For decades, ball marks on clay were part of how athletes formed confidence mid-rally, especially in close calls.. When ELC becomes the final authority, players must suppress that learned instinct: ignore the mark, wait for the system.
This recalibration affects more than just rules.. It can change how players manage momentum and emotion.. Some athletes clearly prefer the consistency ELC brings because it reduces the uncomfortable dynamic of watching an official interpret a mark that may appear different to the player.. Others want a return to the older framework where the umpire inspects, explains, and owns the decision.
Still. there’s a reason ELC is broadly defended by players who like it: it can remove the human reluctance that sometimes surrounds admitting error.. In clay’s high-stakes points. it’s easy to imagine how an official might hesitate—or how a player might feel they’re being dismissed.. Electronic systems eliminate that “will they admit it?” question, replacing it with a standardized procedure.
At the same time, the sport has learned that technology doesn’t erase disagreement—it relocates it.. Earlier eras of line technology created similar frustrations because viewers saw replays that suggested different outcomes. but the match officials couldn’t act on them in real time.. Even today, broadcast replays are often top-down, while players are focused on the ground-level traces they can physically see.. That means the audience experience can still diverge from the athlete experience.
What could change next?. Expect more emphasis on explanation—especially for clay.. If players keep confronting “ball-mark proof” that ELC overrides. the sport may need clearer guidance on why marks can mislead. and how athletes should interpret what they see during critical moments.. Because while the controversy might involve a tiny fraction of all points across a tournament. it concentrates attention where pressure is highest.
For now. players like Iga Świątek appear to be choosing a practical mindset: accept the system and reset quickly. because there isn’t time to wrestle with philosophy between serves.. But as long as clay keeps producing visible “evidence” and ELC keeps making technical calls that sometimes contradict it. the same question will keep returning—can the sport be fair without believing what the ground is showing you?