British Cameron Norrie has been beaten by Teenage American Tien qualifying students in the opening round of Mexico Open in Acapulco.
Norrie, who is now 74th in the world, was defeated 7-6 (7-5) 6-3 by a 19-year-old player, who was ranked nine places underneath.
The British had won one previous meeting between the couple, in Hong Kong earlier this year.
Tien led 4-1 in the opening before Norrie recovered and served to set in 5-4. But he was damaged and Tien continued to take the next bond and control the match after that.
The second seed Casper Ruud advanced to the second round by beating Arthur Rinderknech from France 6-4 6-3 while American pair Tommy Paul and Ben Shelton, third and fifth seed each, also passed.
