US Open: Cause for concern as Novak Djokovic's practice match lasts just three games

The tennis great has played very little tennis in recent months, but that is by choice as he prefers to put all his energy into the Grand Slams, often playing no warm-up tournaments before a major.

Djokovic, though, made a slight tweak to his schedule ahead of the US Open as he signed up for the Cincinnati Open, making his first appearance there since winning the title in 2023.

But his campaign lasted only one match as he was beaten in the round of 64 by Thiago Agustin Tirante and after the encounter, the 39-year-old - who vomited mid-match and required medical attention - revealed he was struggling with "a lot of issues".

"It's just a condition that I have, health-wise, that has been bothering me for the past couple of years. A lot of issues, especially when it is humid and it is hot," he explained.

"I did anticipate it, but there are all these things, like nerves and everything involved that make it worse, and that's what happened."

Despite his health concerns, Djokovic pressed ahead with the US Open's mixed doubles tournament as he teamed up with world No 1 Aryna Sabalenka to take on Henri Patten and Katerina Siniakova on Tuesday.

The top seeds lost 4-1, 1-4, [2-10] on Arthur Ashe, but that was not that for the day for Djokovic, as he had a practice match scheduled against Zizou Bergs later in the day.

However, Djokovic struggled throughout the contest and he eventually called it off after 40 minutes while trailing Bergs 3-0.

There were no signs of an injury, but the 24-time Grand Slam winner looked fatigued after playing a competitive match earlier in the day and given his comments after his Cincinnati exit, there could be alarm bells going off.

Djokovic is due to return to the practice courts at Flushing Meadows on Wednesday as he is scheduled to take on Alexander Zverev at 15:00 local time.

And even if he is not 100% after Tuesday's double action, he has another couple of days to recover as the main draw for the singles will only get underway on Sunday 30 August with the first-round matches spread over three days.

Djokovic is seeded fourth at the US Open, which means he can only meet defending champion Carlos Alcaraz or top seed Alexander Zverev in the semi-final or final.

Last year, the Serbian was beaten in straight sets in the semi-final by Alcaraz.

READ MORE: Carlos Alcaraz reveals why returning at US Open was 'not an easy decision'