23-time Grand Slam champion Novak Djokovic was taken off guard by the fireworks set off across from the Cincinnati Open venue just as he was about to serve for the match against Alexander Zverev.

Djokovic has displayed some of his best form at this week's Western & Southern Open in Cincinnati. After his first-round opponent, Alejandro Davidovich Fokina, retired from their match due to injury, the 36-year-old defeated Gael Monfils and Taylor Fritz to reach the semi-final against Zverev.

Djokovic seemed to have little trouble dispatching the German player. Although the first set went to a tiebreak, the Serb won in straight sets, meaning he is yet to drop a set in the ATP Masters 1000 tournament as he goes into the final against world No. 1 Carlos Alcaraz.

However, as Djokovic was preparing to serve for the match at 6-5 in the second set, he was interrupted by the weekly Saturday night fireworks coming from Kings Island Amusement Park, directly across from the Cincinnati Open venue in the Lindner Family Tennis Center, itself within the Golf Center at Kings Island. 

Djokovic was bouncing the ball on the ground when he heard the fireworks, stopping to pace his side of the court as he waited for them to finish. He appeared to see the funny side though, smiling as the fireworks continued. Meanwhile, the crowd gasped and laughed.

Under a clip of the incident posted on Reddit, one user pointed out that "The whole crowd was laughing cause of the timing," due to the fact that Djokovic was on the verge of winning the match.

Meanwhile, the commentators expressed their confusion as to why tournament organisers had apparently not made the players aware that the fireworks could potentially go off during their match.

"I'm surprised that he [Djokovic] is surprised. I would have thought that the tour supervisors, the tournament referee, or someone would have advised the players beforehand that this was going to happen at 10 O' clock because it is scheduled, it's a Saturday night here at Kings Island Amusement Park," one said.

"Not unexpected. But it appears to be to the players," another added.

After the match, Djokovic signed the camera lens with the words "Fireworks. Yeah"