For tennis players, the sun is an occupational hazard. Especially when executing a service toss around high noon.
"It's like an outfielder trying to catch a fly ball," top-ranked American John Isner said. "You see it all the time that they lose the ball in the sun. We lose balls in the sun all the time as well."
The process of keeping an eye on the ball, after lifting it overhead and directly in line with Sol, is just one more potential peril at an event such as the U.S. Open. It is not unusual to see a player repeatedly look up to gauge the sun's angle before serving, sometimes adding a practice toss.
Tennis, after all, is a sport that literally follows the sun, with the majority of the pro tour contested outdoors and often in warmer climes, beginning the calendar year Down Under in Australia's summertime. Yet the challenge of having to regularly spy a yellow tennis ball in a sky with a big white ball of light is ongoing.
"I actually asked John [Isner] the same question ," said No. 4 women's player Caroline Wozniacki. "Because, sometimes - in Australia, especially - the sun is right in your face and it's really hard.
"Here, you can kind of throw the ball a little bit to the left or a little bit to the right and kind of work with it. But you just know it's the same for the opponent, so you just have to go with it.
"I don't [change the] position of my stance, just my aim. You need to make sure you get up to the ball with perfect timing, because you have less of a margin when you move the ball around."
Defending Open champion Marin Cilic of Croatia called it "always tricky" to adjust a toss to keep the sun out of his eyes, "looking more to one side so the sun doesn't bother me so much. And that's always going to play around with your effectiveness on your serve."
More difficult, even, "is the first shot after the serve," he said, "still having the sun in your eyes."
So why, one might ask, don't more tennis pros play in sunglasses?
In the end, the lack of sunglass-wearing tennis pros comes down to doing things the way they've always been done.