The 7-6 (7/3), 6-4 defeat against the qualifier was 12th seeded Bouchard’s 12th loss in her last 14 matches and will see her drop out of the world top 20.
The 21-year-old Canadian was one of the show-stealers at Wimbledon in 2014 where she delighted fans and media with her fondness for pop star Justin Bieber and TV show The Big Bang Theory.
But she has been in a slump since mid-March, falling in the first round of the French Open and picking up a tournament-ending abdominal injury in the Eastbourne grass-court event.
On Tuesday, she committed 10 double faults and 23 unforced errors against Duan, who had never previously beaten a player inside the world top 75. – Agence France-Presse