Tennis spent the offseason rewriting how it handles extreme heat. On Tuesday in Memphis, the sport got its first significant test of that framework on American soil, and it produced a four-hour stoppage, a top-20 retirement and a 16-year-old qualifier winning the biggest match of her life in tears.
Play at the Leftwich Tennis Center was suspended at roughly 1:30 p.m. local time and did not resume until about 5:30 p.m., FOX13 Memphis reported, as the wet bulb globe temperature climbed past the level at which the WTA halts competition. Ekaterina Alexandrova, the top seed at the inaugural Memphis Classic, retired from her first-round match against fellow Russian Kristina Liutova after 3 hours, 11 minutes, trailing 7-6 (2), 4-6, 5-4 and two points from defeat. The WTA said the world No. 19 stopped because of heat illness.
The technical distinction at the center of the day is what makes this a policy story rather than only a medical one. Wet bulb globe temperature is not air temperature. It folds humidity, wind speed, sun angle and solar radiation into one figure describing how effectively a body can shed heat, which is why a WBGT reading usually runs below the number on a thermometer and is far more useful to a tournament doctor. The WTA has measured the index since 1992. Under the women’s tour policy, play stops once WBGT exceeds 90 degrees Fahrenheit.
That figure should sound familiar to anyone who followed the men’s game this winter. In December, the ATP board approved the tour’s first formal heat rule, effective from this season, built on the same index. It permits a 10-minute cooling break after the second set of a best-of-three singles match once WBGT reaches 30.1 degrees Celsius, and suspends play outright above 32.2 C — which is 90 F, the identical trigger the women have used for three decades.
The ATP described the change as “strengthening protections for players competing in extreme conditions.” It followed a bruising October in Shanghai, where multiple players retired in heavy humidity and the absence of any written men’s standard became the story of the tournament.
Memphis, then, was not a test of the new ATP rule. The Memphis Classic is a WTA 250, and what ran on Tuesday was the older women’s policy. But it was a live demonstration of the standard the men’s game has just spent a season adopting, and it showed both what the rule does and where it stops. It cleared the courts for four hours. It did not prevent the tournament’s highest-ranked player from breaking down in a match already underway.
Where the framework becomes genuinely inconsistent is at the majors. The ATP’s announcement made no claim over the Grand Slams, and the four events continue to set their own rules — a point worth stating plainly, because at least one outlet reported at launch that the new policy extended to the Slams. It does not. Roland Garros and Wimbledon operate WBGT-based policies; the Australian Open uses a separate Heat Stress Scale keyed to roof closures. At Roland Garros in May, an unprecedented heat wave passed without the policy being activated at all.
For an American audience, the relevant question is what happens at Flushing Meadows next month. Tennis.com reported last year that the USTA added WBGT monitoring in 2024, with the tournament medical team taking readings every 30 minutes, but that the US Open — like the Australian Open — has stopped short of adopting a mandatory suspension threshold of the kind now written into both tours’ rulebooks. That leaves the sport in an awkward position heading into its biggest hard-court fortnight: a tour-level rule that halts play automatically, and a major where the same conditions are handled at officials’ discretion.
The Memphis conditions were not an outlier, either. Dorian Burnette, an associate professor of atmospheric science at the University of Memphis, told FOX13 that studies consistently show an increasing frequency of dangerous WBGT stretches, particularly ones offering no overnight relief. The station reported the city now averages just over six heat waves a year, more than double its 1970s rate, and has already recorded three in 2026.
Liutova, ranked No. 229 and making her WTA main-draw debut, became only the second player born in 2010 to win a tour-level match. Hers was not the only marathon on site: American Caty McNally also needed 3 hours, 11 minutes to get past Wang Xiyu, 4-6, 6-3, 7-6 (5), saving four match points along the way.
