Angelique Kerber through to second round of Olympics

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.