British number one Katie Boulter lost nine games in a row as she was beaten 2-6 6-0 7-5 by Magda Linette in the Cincinnati Open first round.
Boulter broke Linette twice in the opening set to take the lead but Poland’s world number 43 responded in impressive fashion.
Linette dominated the second set – dropping just eight points – to ‘bagel’ her British opponent in just 25 minutes.
The Pole then powered into a lead at the start of the third set, earning her fourth-straight break of serve to move 3-0 up.
Boulter, the world number 30, clawed her way back into contention to level the set at 4-4 and saved two match points at 5-4.
But she was unable to save a third match point on her next service game as Linette booked her spot in the second round, where she will face either Wang Xinyu or Liudmila Samsonova.