Anne Keothavong was beaten by second seed Angelique Kerber in the second round of the Copenhagen Open.
The British number two took the first set but Germany's Kerber, ranked 16 in the world, fought back to win 4-6 6-3 6-3.
Keothavong had seen off Hungarian qualifier Melinda Czink in the first round in Denmark.
But after an impressive start against Kerber, she was soon pegged back by the 24-year-old, who won her maiden WTA event at the Open GDF Suez in Paris earlier this year.
Kerber will now face compatriot Mona Barthel in the next round.
Elsewhere, Caroline Wozniacki boosted her hopes of a third consecutive title in the event with an easy 6-2 6-1 win over Pauline Parmentier of France.
The former world number one needed just 67 minutes to brush aside the challenge of the world number 58, with the Dane breaking her opponent five times in total.
Wozniacki is now 12-0 in the tournament and has won 17 straight sets.
Third seed Jelena Jankovic also made it through with a 6-3 6-1 win over Russian wild card Yulia Putinseva, but fourth seed Monica Niculescu went down 6-7 (8-6) 6-4 6-1 to Bojana Jovanovski of Serbia.