Seven-time Wimbledon champion Serena Williams recovered from being a set down to beat teenage qualifier Kaja Juvan and reach the third round.
Williams was surprised by the 18-year-old world number 133 from Slovenia, who twice broke serve to win the first set.
The 11th seed, 37, responded to take control in the second and eventually closed out the decider for a 2-6, 6-2, 6-4 victory in one hour 36 minutes.
“She played well and I started out a little slow,” said the American.
“I like the pressure. I would rather be in this position than any other and I play best when I am down sometimes. I am a fighter.”
Williams, who last won Wimbledon in 2016, will face German 18th seed Julia Gorges in the third round.
She is looking to equal Australian Margaret Court’s all-time record of 24 Grand Slam singles titles but has struggled with a knee injury this year.