Winatho produced a pentathlon best and national record of 4184 points at the 2008 Asian Indoor Athletics Championships, but she was pushed into second place in the final 800 metres event, ending up with the silver behind Irina Naumenko. She made her debut on the world stage at the Beijing Olympics in August, but she did not manage to finish the event and dropped out in the third round. She returned to regional success the year after, taking the pentathlon title at the 2009 Asian Indoor Games. She also came close to a triple defence at the 2009 Southeast Asian Games, taking the heptathlon and relay titles, but she was outrun by her Malaysian rival Mohd Khalid in the hurdles. Her appearance in the heptathlon at the 2010 Asian Games was cut short after she fell in the 100 m hurdles and did not finish the competition.