Katie Boulter reached the third round of the Miami Open for the first time after opponent Brenda Fruhvirtova retired with illness.

The British number one, who received a first-round bye as the 24th seed, was leading 7-6 (5) 1-0 15-0 when 16-year-old wild card Fruhvirtova, who appeared to be struggling with the heat, headed to her chair.

The young Czech, who was short on tennis coming into the tournament having been under the weather, called the doctor for the first time leading by a break of serve at 5-4 in the opening set.

Brenda Fruhvirtova retires from the match

That means that Katie Boulter is through to the next round in Miami pic.twitter.com/nUMn6Y5zrp

— Sky Sports Tennis (@SkySportsTennis) March 21, 2024

Boulter eventually took the set in a tie-break and had broken to start the second before Fruhvirtova called the doctor again and then decided she could not continue.

She is not the first player to struggle in Miami this week, with Frenchman Arthur Cazaux collapsing on court during a qualifying match, while Matteo Berrettini looked close to fainting against Andy Murray on Wednesday.

Boulter had made a shaky start and admitted she found it hard to concentrate amid her opponent’s difficulties, telling Sky Sports: “I actually think it’s one of the toughest things to do.

“Halfway through the match I’m seeing her coaches telling her to pull and then she’s not, so obviously there’s a lot going on. One minute she’s struggling to put the ball in the court and the next she’s running 10 shots side to side so it’s a tough mental game.

“For me it was challenging today and I probably wasn’t the kindest to myself but we live and learn.”