Bernard Tomic of Australia advanced to the second round of the Thailand Open when Ivo Karlovic of Croatia retired with a back injury while trailing 6-7 6-4 4-2 on Tuesday.
Tomic, a quarterfinalist in Bangkok last year, will next face 2006 champion Gilles Simon of France.
Other winners include Lukas Lacko of Slovakia, Go Soeda of Japan, Roberto Bautista Agut of Spain, Lukas Rosol of the Czech Republic.
