Britain's Emma Raducanu lost in the first round of the Abu Dhabi Open as she went down in straight sets to former Wimbledon champion Marketa Vondrousova.
Raducanu, 22, was beaten 6-3 6-4 as she proved unable to take advantage of her late wildcard entry to the main draw.
She made a positive start against Czech Vondrousova and led 3-1 after an early break of serve, but she then surrendered the first set by losing five consecutive games.
Vondrousova, who returned from a six-month lay-off in January following shoulder surgery, saved four break points early in the second set before breaking for a 5-3 lead and the chance to serve out the match.