Third seed Karolina Pliskova is out of Wimbledon after losing in three sets to world number 87 Magdalena Rybarikova.
Czech Pliskova, who won the Aegon International at Eastbourne, was beaten 6-3 5-7 2-6 and is the highest-ranked player to exit the women's draw.
Slovakia's Rybarikova only returned to the tour in February after a seven-month lay-off with injuries.
"I am speechless right now," said the 28-year-old, who has now won 15 of her 16 grass-court matches this summer.
Rybarikova, who reached a career-high ranking of 31 in 2013, had surgery on her left wrist and right knee in 2016 and missed the rest of the season after a first-round defeat at Wimbledon last year.