Boulter

Muchova broke 29-year-old Boulter’s serve twice in the first set and only needed one more in the second set to go 6-5 ahead before she wrapped up the victory.

Elsewhere, British number four Fran Jones also exited the tournament, retiring in the second set of her match with American Jessica Pegula through illness.

Jones, 25, had knocked out Venus Williams in the first round despite feeling under the weather but struggled against Pegula.

Pegula had won the first set 6-1 and despite a medical timeout Jones, who was seen coughing several times during the match, decided at 3-0 down in the second set she was not well enough to continue.

“I didn’t want to lose the opportunity to play Venus, but it’s a whole different ball game playing Jess,” Jones said.

“You need to be 10 out of 10 to compete against her and I’m probably a four out of 10 today. If I’m not able to give my everything out there, I don’t see the point when I’m already battling my general fitness as it is.”

Britain’s Katie Boulter was unable to build on a superb start as she lost to Italian top seed Jasmine Paolini in the last eight of the Merida Open.

Against the world number seven in Mexico, Boulter won the first set in 28 minutes without dropping a game.

But errors started to creep in as Paolini went on to win 0-6 6-3 6-3.

Having won only three points on her serve in the opening set, Paolini started the second set strongly, holding for the first time and then breaking to go 3-1 up.

Boulter, who came into the contest on the back of a seven-match winning run, including claiming the Ostrava Open title, broke straight back to love but neither player could hold serve in the next three games.

It was Paolini who held her nerve to take the second set and level the contest.

The 2024 Wimbledon and French Open finalist raced into a 2-0 lead in the decider and, although Boulter broke back and held serve to lead 3-2, the Italian’s confidence grew as she won four games in a row to claim a semi-final spot.

“It was a really tough one – Katie, the first set she was smashing every ball and hitting a winner everywhere,” Paolini told Sky Sports.

“I was telling myself to play more deep in the court and hit the ball harder because I had to raise the level to try and win the match and in the end it worked out.

“I was trying to be calm, to think what I had to do. I think when you’re nervous you can’t find the solutions.”