New British number one Heather Watson wasted three match points as she crashed out of the AEGON Classic in Birmingham on Tuesday.
The Guernsey 22-year-old fell 2-6 7-5 6-4 to Canadian qualifier Aleksandra Wozniak after a first round match lasting two hours and 12 minutes.
Watson held a 5-3 lead in the second set and served for the match but her lower-ranked opponent rallied and held her nerve in a tense final set.
It was a disappointing result for Watson, who jumped above Laura Robson to 69th in the world rankings after reaching the second round of the French Open last month.
Her exit at Roland Garros had ended a nine-game winning streak made all the more impressive given a shoulder injury which kept her out for two months earlier this year.
Watson had been granted a wild-card for Birmingham and looked ready to set up an all-British second round clash with Johanna Konta after breaking Wozniak three times in the opening set and moving to the brink of victory.
But Wozniak hit back to win four straight games and although Watson recovered from a break down in the final set to draw level at 4-4, it was the Canadian who edged home.
Watson made a strong start, breaking her Canadian opponent three times in the opening set, but began to flag and Wozniak surged back.
Konta had no such problems as the 23-year-old earned an impressive 6-3 6-1 win over Japanese 14th seed Kurumi Nara, who is ranked 71 places higher than the Briton in the world rankings.
Naomi Broady put up a brave fight before falling 5-7 6-4 6-3 to world number 62 Barbora Zahlavova Strycova of the Czech Republic.