Laura Robson lost to the former world No 1 Caroline Wozniacki for the second time in three weeks after succumbing in straight sets at Eastbourne.
The 19-year-old failed to take advantage of the Dane's poor form at the French Open and did not make amends on the South Coast, losing 6-4, 6-4.
Robson, preparing for her 11th Grand Slam appearance at next week's Wimbledon, outplayed Wozniacki in the first set but was made to pay for her unforced errors.
The decisive moment came in the ninth game, with a pair of double-faults in quick succession allowing Wozniacki to break for 5-4 and then serve for the set.
It was a pattern that continued in the first game of the second set, with three consecutive mistakes allowing Wozniacki to come from 40-15 behind to break Robson.
The 2008 Wimbledon girls' singles champion rallied well, though, showing good composure to break back in the fourth game to make it 2-2.
However, Robson was eventually undone in the ninth game as Wozniacki broke again.
Heather Watson got off to a frustrating start in her match against Elena Vesnina and was eventually defeated in three sets.
The British No 2 was broken by her Russian opponent in just the third game and the 21-year-old failed to recover in the first set, going down 6-1.
Watson showed impressive character and strength to take the second set, but in the deciding set Vesnina raced into a 5-0 lead after converting two break points, with Watson eventually losing 6-1, 3-6, 6-2.
Elena Baltacha, the former British No 1, went out of the tournament but only after a lengthy battle against Russia's Maria Kirilenko, the world No 10. Baltacha, who won her first title since returning after ankle surgery in Nottingham last weekend, was beaten 4-6, 6-4, 6-3 after more than two and a half hours.
Baltacha took the first set after two early breaks of serve gave her a 4-1 lead, but Kirilenko worked her way back to force a decider. The 29-year-old Briton still had her chances, but, crucially, failed to take two breaks points at 3-3 in the final set.
"That was pretty gut-wrenching, but I must admit I loved every second of it," Baltacha said afterwards. "Maria is a quality player, and she's got a good game on the grass. She has a massive serve. But I think how I dealt with it, how I played, how I moved and tried to execute the tactics that we discussed before, I think I did a good job of that."
Milos Raonic, the top seed in the men's event, was beaten 6-2, 7-6 by Croatia's Ivan Dodig, but Bernard Tomic maintained his progress. The Australian beat France's Julien Benneteau 6-2, 5-7, 7-6 to win back-to-back matches for the first time in a tournament since February.
Britain's Kyle Edmund was narrowly beaten by Gilles Simon, the French second seed, 7-6,7-6. "I was delighted with my performance," the 18-year-old, said. "It gives you confidence. He is 16th in the world and I got pretty close."