Emma Raducanu revealed that she felt “exhausted” during a straight-sets defeat to Argentinian qualifier Maria Lourdes Carle in the first round of the Madrid Open.

The Briton was crushed 6-2 6-2 in one hour and 26 minutes by an opponent ranked 82 in the world, who had claimed her highest-profile win and maiden WTA 1000 victory.

Playing with strapping around the front of her left knee, Raducanu made a host of unforced errors and saw her serve broken six times.

It was a disappointing performance from the 2021 US Open champion in light of the recent resurgence seen at the Billie Jean King Cup and Stuttgart Open.

The 21-year-old’s progress in last week’s tournament in Germany was only halted in the quarter-finals by world number one Iga Swiatek, but that form deserted her against Carle.

Raducanu said she was “tired” coming into the Madrid Open and she blamed the fatigue for her early exit on the clay.

“I would say the last few weeks have been a lot,” she said.

“I think from the performance today it was very clear that mentally and emotionally I was exhausted.

“I was trying to push through and I was just unable to push through today. I guess the sport is just pretty brutal.”

Earlier this month Raducanu helped Great Britain defeat France to secure a place in Billie Jean King Cup finals, but team captain Anne Keothavong still offered a scathing verdict of her performance against Carle.

“I don’t think you can analyse the tennis because Emma the performer didn’t show up today,” Keothavong told Sky Sports.

“And if any athlete doesn’t show up ready to play, you don’t really stand a chance. Credit her opponent, who came out with fire and energy and she was the one who looked up for it and was ready for the fight.

“We talk a lot about head, heart and legs, and if your head and your heart aren’t in it, your legs don’t stand a chance.

“It was really disappointing to see. She said she was tired, but do you talk yourself into more tiredness?”

British number two Harriet Dart followed Raducanu out of the tournament with a 6-4 6-4 defeat by Cristina Bucsa of Spain.

Jack Draper reached the second round through a 6-3 3-6 7-5 victory over Australia’s Thanasi Kokkinakis.