Birmingham - Agnieszka Radwanska, the top-seeded former Wimbledon finalist, lost her first match of the year on grass Wednesday, going down 7-5, 4-6, 6-3 to world No 32 Coco Vandeweghe at the Birmingham WTA event.
It was a setback which was particularly hard to take for a player who has reached the semi-finals or better in nine of her last 13 tournaments.
More incongruous still, Vandeweghe had lost all four of their previous encounters, winning a mere 18 games in the process.
But the powerfully built American's timing and confidence were in good order after winning the 's-Hertogenbosch title on grass last week, while the Pole's practice on this surface had been restricted by repeated rainstorms.
Vandeweghe's career-best win was achieved with a determination to swing hard whenever she could, and a belief that she could over-power her opponent even if she sometimes missed.
The policy was particularly effective against Radwanska's moderately paced second serve, a delivery which was heavily punished in the seventh and ninth games of a final set, just when many thought the favourite was turning things around.
"I got into trouble (in the second set) but I managed to get through it," said Vandeweghe. "Last week helped me escape from a tricky situation because I had done it before."
The match had had a tricky feeling almost throughout, for it was stopped at four games all the previous night, and was halted again for nearly an hour Wednesday early in the second set.
"The rain delays didn't help because you have to keep your mind on the match, which isn't always easy," Vandeweghe said.
"I tried to keep myself quiet, and I thought if I could stick with my game plan (hard, flat attack) I could do it."
Radwanska was philosophical with Wimbledon less than two weeks away.
"I don't think I played so bad today - she was just really good," she said.
Belinda Bencic, the youngest player in the top ten, suffered another injury less than two weeks after returning from more than two months away with a bad back.
The 19-year-old Swiss player quit while trailing 6-4, 4-3 in her first round match against Irina-Camelia Begu, the world number 26 from Romania.
Bencic hurt her right thigh in a fall on the slick grass in the first game, and by the fifth game has called the trainer.
But she continued, often with her movement looking limited, and rarely looked capable of winning the match.
"I played more than I should have," she admitted
Last week, Bencic contested four grass court matches in the Netherlands, her first tournament since early April, which makes this latest setback particularly ill-timed.
Almost inevitably the weather deteriorated again, placing Caroline Wozniacki, the former world number one from Denmark, in a similar situation to that of Radwanska on Tuesday - being obliged to finish early by repeated rain.
Wozniacki leads Yanina Wickmayer of Belgium 3-2 and the winner is scheduled to play twice in one day on Thursday.