World number three Coco Gauff lost in 73 minutes to Marta Kostyuk in the second half of Qatar Open.
Ukraine, world number 21, against 3-1 in the second set to end the 6-2 7-5 victory at the 1,000 WTA event in Doha.
This is the second successive defeat for Gauff, who received Bye in the first round and played for the first time since he was Lost from Paula Badosa In the quarter -finals of the Australian Open last month.
US Open Champion 2023 was canceled by seven double errors and 39 mistakes that were not forced while he only managed eight winners.
Gauff has won the last 17 matches against opponents ranked outside 20 before facing Kostyuk.
The 22-year-old player will now face the winners of all-patterns between Magda Linette and Magdalena Frech.
Elsewhere, former Wimbledon champion Elena Rybakina claimed a 6-2 6-4 victory against American Peyton Stearns, while Jasmine Paolini-Wimbledon last year and Runner-Up French Open-defeated Caroline Garcia 6-3 6-4.
Linda Noskova won 6-2 6-3 against Yulia Putintseva from Kazakhstan to hold the last 16 meeting with the defending champions three times the Swiatek ribs.
