There were worrying scenes on Margaret Court Arena on Sunday as a ball kid collapsed in the middle of a match.

Tim Puetz and Demi Schuurs were facing Aussie duo JP Smith and Kimberly Birrell in the mixed doubles when fans alerted the players that a ball kid looked unwell.

Sunday marks the hottest day of the Australian Open so far.

After losing the first set, Puetz and Schuurs were trying to get back in the match as they served at 1-1. But after celebrating a point, they quickly realised something was wrong with the ball kid at the baseline.

Puetz rushed over and put his arm around the child, who appeared woozy and fainted in his arms. The umpire called for help and the players and umpire rushed over.

"There clearly was a little bit of distress. It's been a scorcher of a day, over 30 degrees celcius," Chris Bradnam said on commentary. "Need an ice pack and some fluid pretty quickly."

Anne Keothavong added: "Not what you want to see but everyone doing their best to help. Help is on the way. Not easy out there for anyone."

Medics quickly arrived to help the ball kid and were seen talking to the child. "Horrible to see, they do such fantastic work," Bradnam remarked.

Staff members held towels up to give the ball kid some privacy while the medics continued to help and Eurosport cut away from the match. Pundits later confirmed the child had fainted due to extreme heat and left the court in a wheelchair.

Rachel Stringer said: "We just saw a ball kid has fainted due to the extreme heat today. It’s hot out there.

"The conditions are testing not just for the players but for everybody involved in making this tournament a success. You can see them being wheeled off the court.

"We’re hoping they make a speedy recovery and it’s not too serious. Our thoughts are with that kid there."

John McEnroe explained just how hot it was in Melbourne, adding: "Conditions are pretty brutal. It's currently about 32 celsius. Even toastier when you're on a hardcourt surface, the cement surface.

"Needless to say it’s important to get a quick start. I think that’s why you saw Draper stop playing, the heat got to him, you saw he had other injuries from the three five-setters.

"Davidovich Fokina did the same thing. You just don’t have the same will. I’m sitting here thinking I’m going to faint like that poor ball kid."