Frenchman Arthur Cazaux was forced to retire from his Miami Open qualifier against Harold Mayot after collapsing to the floor in the third set.
Cazaux has been rising steadily up the ATP Tour rankings and made a name for himself at this year's Australian Open where he made it through to the fourth round.
He was looking to continue his rise this week in Miami and was up against compatriot Mayot in the qualifying rounds.
There was barely anything to separate them both as Cazaux forced a deciding set after Mayot won the first.
Arthur Cazaux collapsed on court
ATP
But play was stopped in the fourth game of the third set when Cazaux collapsed to the floor while waiting for his opponent to serve.
The 21-year-old hit the floor hard before a nearby medic rushed on to the court to attend to Cazaux.
More footage of the court later showed Cazaux being helped into a wheelchair with an umbrella brought on to provide some shade.
It was soon confirmed by the chair umpire that Cazaux was unable to continue with Mayot progressing.
The umpire announced."Ladies and gentlemen, unfortunately, due to illness Mr Cazaux has to retire from the match.
"Match Mayot - 6-4, 5-7, 2-1 retirement."
Temperatures were above 30C with weather forecasters warning of high humidity in the area.
The heat is set to subside later in the week with the men's first-round action getting underway on Wednesday.
Andy Murray has been handed a fascinating clash against Matteo Berrettini, who is on the comeback trail after an injury-riddled 2023 season.
Arthur Cazaux was helped up into a wheelchair
ATP
The 2021 Wimbledon finalist has dropped to 125th in the world rankings, but has used a protected ranking to qualify for the main draw of the Miami Open.
Murray's compatriots Jack Draper and Dan Evans are also in first-round action against Taro Daniel and Lorenzo Sonego respectively.
Cameron Norrie has received a bye into the second round due to being one of the 32 seeded players.
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Arthur Cazaux appeared to be affected by the heat
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In the women's draw, Emma Raducanu faces China's Xiy Wang in the first round after being given a wildcard entry.
Katie Boulter also competes in her first tournament as a seeded player owing to her win in San Diego earlier this month.
She enters the Miami Open as the No 24 seed and will face either a qualifier/ lucky loser or Brenda Fruhvirtova in the second round.
