Obviously Roger Federer's humidity-induced loss to John Millman has accentuated the attention on the weather at this US Open, as often happens when things involve Federer.
Combine Federer's loss with Novak Djokovic's MTO in the third set against Joao Sousa, Maria Sharapova taking another dispiriting loss at a major, and the highly anticipated Osaka/Sabalenka match, and it makes sense that even hardcore tennis fans were not devoting social media attention to the Lesia Tsurenko/Marketa Vondrousova match.
The US Open wasn't either, as it was the last singles match played on Grandstand for the tournament, the deemed "ugly duckling" on the day's schedule, just as Sevastova/Svitolina was the day prior.
Setting aside the fairness of having 7/8 matches play under a roof and a single match off Ashe and Armstrong, Tsurenko and Vondrousova were also struggling in the conditions.
I didn't see the whole match, tuning in at the end of each set via ESPN's still-inexplicably-delayed streaming on the app, but Tsurenko appeared to be in deep trouble, down a set after losing a tiebreaker, and having called for medical attention in the difficult environment (though Vondrousova wasn't exactly convinced of it, judging by her press conference comments).
By the time I returned, the second set was at the business end, and Tsurenko pulled through as Vondrousova's level appeared to be dropping in part due to issues with her right thigh that was already wrapped. From what little I saw, the third set seemed to be the same story, and the veteran prevailed.
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One of the primary narratives of Grand Slam tennis is when it's appropriate to close a roof. Should all competitors be on a level playing field, or should governing bodies take a "save who you can and seal the door" approach, giving the elite players yet another advantage in the name of higher quality tennis and fan experience?
Here's the thing: on Day 9, this doesn't even need to be an issue! (And really, it could happen by Day 7 if that one Grandstand match is moved to Armstrong).
At this point, all matches are on Ashe, with a roof that doesn't take long to open or close. In conditions as brutal as this week, what's the harm in closing the roof if both players agree? From the players to the spectators (many of whom have spoke of their misery in the Ashe greenhouse on Twitter) to TV viewers, would anyone not benefit from the Del Potro-Isner and Nadal-Thiem matches being played indoors?
Maybe Delpo (willing to suffer in order to not aid Isner's serve) and/or Thiem (feeling that braving the humidity better than Nadal, as he did at Buenos Aires 2016, is his path to victory) decline the option, but I don't see the downside of at least having that on the table.
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Speaking of Nadal-Thiem, I do think Nadal is in significantly greater jeopardy due to the humidity.
When Nadal is fatigued, especially mentally, that's when his ball can get shorter. With Thiem, fatigue actually makes him more aggressive, Often that's to his own detriment, but as we saw at Rome 2017, it worked when a tired Domi went for broke and redlined against a similarly-exhausted Nadal (Thiem finally hit empty the next day, running out of fuel before even leaving the driveway in his semifinal against Djokovic).
Nadal has again repeated his mantra of dictating offense and not letting his opponent take control, but I actually think a critical part of him winning involves taking a page out of Federer's unsuccessful playbook from Monday night.
Coming off two very physical matches, combined with two days off and less-oppressive weather looming, this is the final match this tournament where Rafa should actually be the one shortening points (the first being when he was hurting and needed to hit bigger against Khachanov to have a chance).
Taking that into consideration, dropshots should be a core element of Nadal's gameplan on Tuesday night. They didn't work great for Federer, but Thiem's court positioning projects to remain conservative, and even if the droppers aren't perfect, variety has been a key in Nadal's history with Thiem, who is one of the few players who can "out-suffer" the defending champion.