Germany's Angelique Kerber has reached the second round of the women's singles at the Olympics after Czech opponent Petra Cetkovska retired.
The world number seven raced into a 4-0 lead in the opening set by breaking twice before her opponent got on the board in game five.
Kerber wrapped up the set 6-1 in just 20 minutes before again marching to a 3-0 lead in the second.
Cetkovska was clearly unhappy and after a lengthy delay decided to call it a day.
Kerber, seeded seven in the singles, will next face Timea Babos of Hungary for a place in the third round at the All England Club.
