Tennis umpires are making match-defining calls by tracking marks in the clay, and stars say it's time to go digital

• Tennis pros — including Denis Shapovalov, Stefanos Tsitsipas, and Dominic Thiem — are calling on the French Open to introduce shot-tracking technology such as Hawk-Eye and FoxTenn at Roland-Garros.
• Stars at the Grand Slam have grown increasingly frustrated with umpires making match-defining — and sometimes incorrect — decisions based off of marks in the clay and the naked eye alone.
• The French Open is the only Grand Slam event that has yet to implement the use of simulation technology to more accurately pinpoint where balls strike the court.

Many aspects of the game of tennis have advanced considerably in recent years.

But in some regards, the sport's officiating has been left in the dust.

Such is the case at the French Open, where umpires call shots in or out based on marks in the clay and the naked eye alone. Unsurprisingly, a system subject to human error such as this one often results in inaccurate judgments — from umpires focusing on stray marks in the clay, balls leaving unclear impressions in the dirt, or line judges mistracking shots.

Stars at the Grand Slam have grown increasingly frustrated with the powers-that-be making match-defining decisions based on unreliable methodology. And now, calls to implement technology designed specifically to track tennis shots with pinpoint accuracy — such as Hawk-Eye and FoxTenn — are growing louder by the day.

After losing a five-set thriller to Roberto Carballes Baena Thursday — and finding his own match marred by a crucially miscalled shot — Canadian star Denis Shapovalov took the question on everyone's mind to Twitter.

"When are we going to have Hawk-Eye on clay @rolandgarros @atptour?"

He's far from the only one. World No. 6 Stefanos Tsitsipas said he believes "they should implement that into tennis" because "technology allows us to do far more things than current knowledge allows us."

"Doesn't really matter the surface," the Greek superstar added. "That's innovation, and we have to keep growing and keep adding new things to the sport that will help make the sport better and more fair ... So I fully support that there should be Hawk-Eye in every surface on tennis, regardless of whether it's clay or grass."

Roland-Garros is the only Grand Slam tournament that has yet to turn to computer systems as a means of making pivotal calls on the court. The US Open first began implementing Hawk-Eye technology in 2006. The following year, the Australian Open and Wimbledon followed suit.

As of 2016, more than 80 tournaments used the technology to help improve the accuracy and fairness of calls, according to the company that produces the line-calling service. Clay events have been notoriously slow to evolve, but Austrian Dominic Thiem said he didn't face "any issues" at the Rio Open after the tournament became the first clay competition on the circuit to use FoxTenn.

Thiem, who won the US Open just last month, agreed with Shapovalov and Tsitsipas about Roland-Garros adapting to the times.

"I would 100% support Hawk-Eye on clay," Thiem said, per journalist Max Gao. "Today in my match there was a mistake in my favor actually. Casper [Ruud] showed me the mark on his phone after the match in the first game of the second set."

The world's third-ranked player insisted that "it's not the umpire's mistake" in every instance. Instead, he noted that court cleaning and brushing the lines makes it "almost impossible to see where the mark starts."

"So I think it would be fair for everybody if Hawk-Eye would also exist on clay," Thiem said. "So I think we should make it happen.

"I hope that next year we will have it in every clay court tournament," he added.

• Read more:
• Serena Williams had her earliest exit from a Grand Slam in 6 years due to an injury, and now it might shut her down for the rest of the year
• A French Open match came to an ugly ending with the world's 5th-ranked player in tears after her opponent thought she was faking an injury and cursed her out
• How Coco Gauff became a bona fide tennis superstar at just 16 years old
• How Naomi Osaka rose to the top of the tennis world and became a leading voice for social justice