Defending champion Elena Rybakina recovered from a poor start to avoid a Wimbledon first-round exit against American Shelby Rogers.
The Kazakh, whose title defence began with a double fault, won 4-6 6-1 6-2.
Her build-up had been hampered by illness and she lacked energy against the world number 49 at the start.
But there was a dramatic shift in momentum as Rybakina avoided becoming the first women's defending champion since 1994 to lose at this stage.
Steffi Graf was the champion who fell at that hurdle 29 years ago when she was beaten by American Lori McNeil - and after an error-strewn first set it had looked as if Rybakina would be joining the German in the history books.
But watched from Centre Court's Royal Box by both tennis royalty and actual royalty in the shape of Roger Federer and the Princess of Wales, the 24-year-old battled to hold on to her own crown a little longer.
Rybakina got off to a shaky start, dropping serve in the opening game and serving two double faults in her first two service games, and she struggled to recover as a composed Rogers went on to seal the first set with an ace.
But it was soon the Kazakh who held all the aces, delivering five of them in a dominant second set that she whizzed through in 29 minutes as rain hammered down on the court's closed roof.
She broke in the opening game of the third set when a wide-looking forehand was shown to be in by Hawk-Eye and maintained the advantage, wrapping up victory when Rogers could only net a return.
"It was really tough for me today, I was really nervous," Rybakina said in her on-court interview. "The double fault said it all at the beginning of the match."
She will play France's Alize Cornet or Japan's Nao Hibino in the second round as she bids to become the first woman since Serena Williams in 2016 to defend the women's singles title here.
Later on Tuesday, Australian Open champion and Wimbledon second seed Aryna Sabalenka is due to open her campaign against Hungary's Panna Udvardy, while last year's Tunisian runner-up Ons Jabeur takes on Poland's Magdalena Frech.
Two-time Wimbledon champion Petra Kvitova of the Czech Republic was also due in action on a day where rain has been disrupting the schedule on the outside courts.
