The emergence of a mysterious illness has started to affect many players performances at this year's US Open.
Ons Jabeur was one of the more high profile names to be struck down by an apparent illness in her first round win against Camila Osorio as she seemed to be having breathing difficulties and also a noticeable cough additionally.
And then that shortly followed by Dominic Thiem feeling he needed to retire after just the one set played in his match against Ben Shelton. Thiem displayed signs of fatigue and was seen vomiting moments before his match, too.
In addition to this, Wimbledon quarter-finalist and home favourite Chris Eubanks required the bathroom midway through the third set of his surprise loss to Benjamin Bonzi. The American soon took some nausea medication during the encounter.
Many players will understandably be quite reluctant to mix with other players in order to stay on the safe side and not risk impacting their own progress at the last Grand Slam of the season. Caroline Wozniacki, who scored a fantastic victory over Petra Kvitova last night, gave her views on the ongoing illness spreading amongst players.
"I haven't been spending much time on-site. I come here to practice and play my matches. That's usually anyway my routine. Usually I love to be the first one on the practice courts and I'm out of here before everyone gets in. Really I try to hydrate and stay healthy. I feel pretty good. So hopefully that is going to continue. I usually stay away from people that look sick anyway. But I haven't seen many people actually in the women's locker room not feeling well."
The extent of how much this ongoing illness will wreak havoc on the draw really remains to be seen, but many contenders for the title will be hoping it doesn't badly impact them over the fortnight of competition.