Third seed Li Na became the biggest casualty of the women's draw so far as she was dumped out by Germany's Sabine Lisicki on Centre Court.
The French Open champion squandered two match points in the third set and was made to pay for her profligacy by her unseeded opponent who showed tremendous character to complete a 3-6 6-4 8-6 victory.
Li appeared on course for the third round as she edged a tight opening set, but she was unable to shake off big-serving Lisicki who won the Edgbaston championship during her warm-up for SW19.
Having claimed a hard-fought second set to level the match, 21-year-old Lisicki then held her nerve to stave off two match points with some huge serving when 15-40 and 3-5 down and went on to break her rival in the next game to stay alive.
Li immediately claimed another break of serve to give herself a second chance to close out victory at 6-5, but again she stumbled as Lisicki reeled off three straight games to clinch a topsy-turvy encounter, sealing victory when Li sent a forehand wide.
Lisicki - who served 17 aces - dropped to her knees in celebration having won and will now face a clash with unseeded Misaki Doi of Japan in the next round.
Schiavone on song
Sixth seed Francesca Schiavone moved into the third round of the women's singles with a 7-5 6-3 victory over Barbora Zahlavova-Strycova at Wimbledon on Thursday.
The Italian, who had beaten Jelena Dokic on Centre Court in her opening match appeared unfazed by the switch to Court Three, booking a clash with Tamira Paszek in straight sets.
Austrian Paszek made her way into the third round at SW19 with a 6-4 6-1 win over Christina McHale.
Ana Ivanovic became the first winner of the day with a straightforward 6-3 6-0 victory over Eleni Daniilidou.
Number 12 seed Svetlana Kuznetsova was also successful on day four, setting up a showdown with Yanina Wickmayer with a 6-0 6-2 defeat of Alexandra Dulgheru.
The 19th seeded Belgian took three sets to book her passage into the next round, beating Anna Tatishvili 3-6 6-4 6-2.
There were no smiles for Anastasia Pavlyuchenkova, though, as the 14 seed saw her Wimbledon dreams shattered by fellow Russian Nadia Petrova.
Petriova's 6-3 6-3 win earned her a clash with Kateryna Bondarenko after the Ukranian beat Sara Errani 6-4 5-7 6-2.
Julia Goerges, the German 16th seed, awaits Dominika Cibulkova in the third round after the latter cruised to a 6-1 6-2 win over Polona Hercog.
Goerges progressed via her 7-6 (12-10) 6-2 defeat of Mathilde Johansson, who knocked out Great Britain's Heather Watson on Wednesday.