It is well over two decades since any woman other than Serena Williams and Venus Williams successfully defended the women’s title at Wimbledon. Angelique Kerber, who won here in such style 12 months ago, will not be joining them after she was ousted 2-6, 6-2, 6-1 by the American Lauren Davis in the second round.

Davis, at 5ft 2in one of the smallest players on the Tour, only got into the draw as a lucky loser. A brilliant mover, she chased down everything and made the usually rock-solid Kerber miss, with 31 unforced errors from the German telling their own story.

“I was trying to find my game the whole match, actually,” said Kerber, who will drop out of the world’s top 10 after Wimbledon. “I was not really feeling good from the beginning. I don’t know why. The energy was not there. I tried. She played well. She was going for it. She took the match in her hand. I was too defensive in the important moments. Of course I’m disappointed. It’s not the way I would like to finish here or to play here. But you have sometimes days like that. You have to accept it. You have to learn from it, try to forget this as soon as possible.”

Davis was ranked inside the top 30 just two years ago but injuries have dropped her down to her current mark of 95. Here, though, with Kerber off-colour, she took full advantage to take her place in the third round, where she will play Carla Suárez Navarro, the No 30 seed from Spain. Having lost in the final round of qualifying, it is almost like she’s playing with house money and she is enjoying the ride.

“It’s definitely been incredible,” she said. “I was super-disappointed, having lost last round of qualies. I found out less than two hours later that I got into [the] main [draw]. I was ecstatic about that. It’s honestly a dream being here. I played qualies last year, so I wasn’t able to come here. It feels amazing.”

Serena Williams celebrates during her 2-6, 6-2, 6-4 against Kaja Juvan of Slovenia. Photograph: Will Oliver/EPA

Meghan, Duchess of Sussex, was there to watch Serena Williams in her second-round match against Kaja Juvan, an 18-year-old Slovenian who likes the philosophy of Socrates and Descartes. Her tennis wasn’t bad, either, as she took the opening set against a rusty-looking Williams but the American, trying to equal Margaret Court’s all-time record of 24 grand slams, pulled her game together when she needed it. Her 2-6, 6-2, 6-4 victory sets up a third-round meeting with the 18th seed, Julia Görges of Germany. “It was definitely coming together as the match went on,” Williams said. “I’m just low on matches basically. I could feel it. But I’m getting there.”

She will get plenty of matches if she keeps going deep into the second week as she partners Andy Murray in the mixed doubles. While the media might like to claim credit for putting the pair together, Williams said she and Murray had discussed it a few days before and were excited to get on the court together. “It made sense for me because I really could use some matches at this point,” she said. “It made sense for him. We both want to do well. We both love Wimbledon. Playing with a British icon like Andy is going to be really exciting. I’m looking forward to sharing the court with him and maybe I can learn a thing or two from him.”

Petra Kvitova, meanwhile, continues to defy expectations as she battles the arm injury that forced her to miss the French Open. The Czech, whose two grand slam titles came here in 2011 and 2014, beat Kristina Mladenovic 7-5, 6-2, serving a whole game of aces early on and saving three set points before pulling away for victory. She will play Mandy Minella, of Poland, a surprise winner over American teenager Amanda Anisimova, who reached the semi-finals at the French Open last month.