The second semi-final at the Paris Masters was halted due to a medical emergency in the crowd.

In the fourth game of the match between Karen Khachanov and home hope Ugo Humbert, the umpire was forced to stop play and announced there had been an "incident", calling doctors.

Medics quickly arrived in the stands while the supervisor took to the court until play resumed.

There was a worrying interruption early on in Khachanov's match against Humbert. Both men were facing off for a spot in Sunday's final but they were made to wait when a fan appeared to be taken ill.

Former champion Khachanov was serving at 1-2 40-40 when experienced umpire Richard Haigh noticed something was wrong. "Ladies and gentlemen, we have a medical incident, we need the doctor," he announced into the microphone before radioing someone on his walkie-talkie.

Haigh got off his chair and headed over as other members of the crowd gathered around. "We just have a medical incident in the stands," commentator Mikey Perera said.

"So of course there will be a little delay in the play to just wait for this to get sorted. We do hope it's nothing too serious. Doctors will be on hand quickly I'm sure."

"The players know the drill. They will just have to wait as long as it takes and wait patiently."

Khachanov paced around at the baseline while Humbert briefly headed to his bench. Haigh could be heard asking whether security or doctors were headed to the stands.

He approached Humbert with an update, informing the Frenchman: "I mean, she doesn’t look very good so it might take a few minutes so I don’t know if you want to wait."

ATP supervisor Gerry Armstrong also took to the court. "I think she’s conscious at the moment. Ugo is fine. If you want to let Karen know, I’ll make an announcement," the umpire told him.

Haigh returned to his chair and took to the microphone. "Ladies and gentlemen, as you can see, we have a medical situation. There will be a slight pause, once we fix this, play will continue," he said.

Three medics could eventually be seen attending to the fan before play resumed. Khachanov initially seemed distracted by the delay and faced a break point.

But he held on and broke in the next game to lead 3-2. However, he couldn't hold onto his lead and some sloppy mistakes allowed Humbert to get straight back on serve.