Petra Kvitova could not join Simona Halep and Garbine Muguruza in the second round on a mixed day for the supposed contenders at Wimbledon that also saw Maria Sharapova sensationally dumped out.
Two-time champion Kvitova was the pre-tournament favourite, but her hopes of adding another title were soon over as she went down to Aliaksandra Sasnovich in three sets.
World number one Halep and defending champion Muguruza had no such problems, as the majority of the other seeds progressed.
Caroline Garcia and Sharapova were not among them, however, the world number six losing to Belinda Bencic in straight sets as the 2004 champion threw away a one-set lead to qualifier Vitalia Diatchenko.
Defeat at the hands of the world number 132 represents the first time that Sharapova has lost in the first round at the All England Club.
FAVOURITE FALLS AT THE FIRST
Kvitova never looked herself and did well to take her match with Sasnovich to a third set before falling well short in a 6-4 4-6 6-0 reverse.
"I was just warming up at 5-0," said Sasnovich. "I could play another match!"
Kvitova struggled for answers: "I just didn't feel well. It was a first round. The nerves were there again. I don't know."
The Czech had been on course for an enticing quarter-final meeting with Halep, but the Romanian will march on towards a seemingly more favourable clash after beating Kurumi Nara 6-2 6-4.
MUGURUZA FEELS THE LOVE
Muguruza was up against a home hopeful in Naomi Broady, with the crowd on Centre Court seemingly partisan at times as they roared on the Briton.
But the defending champion did not see it that way and thoroughly enjoyed her winning return to SW19, coming through 6-2 7-5.
"The atmosphere was good. I know I was playing a British player, but I think the crowd was very fair, very equal," she said. "It's always good to go out there - it's one of the most beautiful courts."
Johanna Konta was one of only two British stars to progress on a mixed day, as 2014 finalist Eugenie Bouchard, of Canada, defeated Gabriella Taylor in three sets.
KERBER SEES OFF FELLOW FINALIST
Two women with experience of a deep run at this tournament went head to head elsewhere, with 2016 finalist Angelique Kerber seeing off 2010 finalist Vera Zvonareva.
Kerber was relatively comfortable in a 7-5 6-3 success, just as Naomi Osaka was able to make light work of Monica Niculescu. The Japanese progressed 6-4 6-1.
Jelena Ostapenko, Daria Kasatkina, Elise Mertens and Ashleigh Barty were among the other seeds to head through.
Roger Federer made headlines on the men's side of the draw this week as he traded Nike for Uniqlo, but female star Halep is sticking with the former.
She was asked by one Chinese journalist if she would consider a change of colour, however, as red - not allowed at Wimbledon, of course - is luckier.
"Maybe I will have a conversation with Nike, but I'm not deciding the colour of my outfit or the outfit. They are the bosses," she said. "I will wear what they give me."
Nike bosses will be relieved, no doubt.