Iga Swiatek was dumped out of Wimbledon in straight sets on Saturday by French veteran Alize Cornet, ending the world number one's 37-match winning streak.
Novak Djokovic clinically disposed of fellow Serb Miomir Kecmanovic as he continued his relentless pursuit of a fourth successive Wimbledon title with a 6-0 6-3 6-4 victory on Friday.
Playing her first singles match for a year after injury, Serena Williams' opening-round Wimbledon loss to Harmony Tan on Tuesday was hardly her most unexpected defeat, but there were plenty of signs it could be the most portentous yet.
Serena Williams returned to singles tennis at Wimbledon on Tuesday after a year away, as she took on unseeded Harmony Tan of France.
Rafael Nadal overcame a scare in his Wimbledon opener on Tuesday, fighting back from dropping the third set and falling a break down in the fourth to eventually see off Argentina's Francisco Cerundolo.