Andy Murray reached the Shanghai Masters second round and world number 553 Wang Chuhan caused a major shock when the Chinese wildcard knocked out 15th seed Fabio Fognini in straight sets on his ATP World Tour debut.
Murray, ninth in the rankings as he seeks to break into the elite top-eight who will play in the season-ending ATP Finals in London in November, overcame Russian Teymuraz Gabashvili 6-1, 7-5.
The Briton broke his opponent three times to run away with the first set but was broken twice in the second and had to dig deep to avoid a decider and set a second-round clash with Jerzy Janowicz.
Wang, who mainly plays in Challenger or Futures tournaments, recorded a 7-6, 6-4 first-round win over Italian Fognini on the Grandstand court to huge cheers from the shocked home crowd.
The 22-year-old showed few nerves as he continued to pound aggressively for the lines against a flat Fognini, who offered little in the closing stages of the match and seemed happy to get off court as quickly as possible.
Mikhail Youzhny also caused an upset, beating 12th seed Ernests Gulbis 6-4, 6-1.
The Russian, who converted three of his four break points and dropped just 10 points on serve, next meets Ivan Dodig, who beat Pablo Cuevas 7-5, 6-2.
Ivo Karlovic, who upset US Open champion Marin Cilic in the first round, belted down 24 aces to beat Yen-Hsun Lu 7 6,