Emma Raducanu was ousted from the Dubai Tennis Championships by lucky loser Antonia Ruzic as sickness and illness continued to take their toll on the British No 1.
Raducanu has been slated to take on Elisabetta Cocciaretto but a thigh injury put paid to the Italian's hopes having played eight matches in the last eight days.
That left world No 67 Ruzic - beaten in the first round of qualifying - to come in as a late replacement just hours before taking to the court.
Raducanu, who two days after losing the Transylvania Open final retired from her first-round match against Camila Osorio at the Qatar Open due to high blood pressure, bowed out 6-1 5-7 6-2.
The British No 1 had both physio and doctor on court after losing the first set 6-1 in 30 minutes but looked much brighter following the medical intervention
The former US Open champion had multiple opportunities to break the Ruzic serve but still appeared slightly restricted with her movement.
Ruzic, the Croatian No 1, came into the contest on a five-match losing streak but closed in on victory at 5-3 up in the second.
However, she was unable to close out the contest, allowing Raducanu to make the all-important breakthrough at the eighth time of asking before making it four games in a row when seemingly on the verge of defeat, to close out a 65-minute second set.
A third-straight break for Raducanu put her 2-0 up in the decider, but Ruzic wrestled back control in a see-saw encounter, winning the next six games to take the set 6-2 and seal victory in two hours and 20 minutes.
The Brit will now aim to get her mojo back in time for the 'Sunshine Double' starting in the California desert at Indian Wells - live on Your Site Tennis from March 4-15.
Canadian teenager Victoria Mboko had earlier withdrawn from the tournament, becoming the latest prominent player to be ruled out due ‌to injury, illness or scheduling changes and leaving seven lucky losers to fill the depleted main draw.
The 19-year-old, who , pulled out with a right elbow issue and was replaced by Croatian Petra Marcinko ​in the main draw.
One of several WTA 1000 tournaments that sit below only the four Grand Slam tournaments in stature, the Dubai event has been hit by a spate of withdrawals, including ​that of top-ranked Aryna Sabalenka due to a minor hip problem.
Iga Swiatek, Karolina Muchova (both ‌schedule change), Maria Sakkari, Zheng Qinwen (both illness) also pulled out.
British qualifier Jan Choinski's run at the Qatar Open came to an end as he lost out to Jakub Mensik in the main draw's opening round.
Choinski, who came through qualifying and beat Quentin Halys in a last-set tie-break to reach the main draw, was beaten 6-7 (6-8) 6-2 6-4 by the Czech Republic's world No 16.
British No 4 Choinski was on course for an upset when he won the first set on a tie-break, but he lost his opening two service games in the second and never recovered as Mensik levelled the match.
World No 124 Choinski then let slip a 2-0 lead in the decider after an early break against Mensik, who hit back to level and broke the Brit again to lead 5-4 before serving out for the match.
Jannik Sinner made a successful debut in the Qatar Open on Monday, beating first-round opponent Tomas Machac 6-1 6-4 in his first career match in Doha.
Second seed Sinner broke Czech Machac in the opening set while not facing a single break point on his own serve.
World No 31 Machac put up more of a fight in the second set but suffered another service break in the fifth game.
Sinner failed to convert three match points on Machac's serve in the ninth game but wrapped up victory in the next game after an hour and 11 minutes on court.
The Italian, who has won all three of his career meetings with Machac, will face Alexei Popyrin of Australia in the second round.
Former Qatar Open champion Daniil Medvedev eased into the second round of this year's event, beating China's Shang Juncheng 6-4 6-2.
Medvedev, who overcame Andy Murray in the 2023 Doha final, broke for a 3-2 lead, then saved a break point against the serve in the next game on the way to taking the first set.
World No 261 Shang failed to show much resilience in the second set, dropping his opening service game before being broken to love and going down 4-1.
Medvedev didn't manage to convert his first match point in the eighth game of the set, but closed it out at the second opportunity.
The fourth seed will meet Stefanos Tsitsipas or Moez Echargui in the second round.
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