Top seed Victoria Azarenka has booked her place in the semi-finals of the women's Olympic singles by seeing off Germany's Angelique Kerber in straight sets at Wimbledon.

In a tight opening set the Belarusian had an early break cancelled out, but she found a decisive second to take it 6-4.

Azarenka held at the start of the second before both players dropped serve in the next four games.

Kerber then got herself back to 3-3, but the German was broken for the fifth time in the match, allowing the Australian Open winner to serve out the contest.

However, Azarenka was unable to take three match points as Kerber broke back to get herself back on terms.

It ultimately mattered little as the world number one broke for a final time to win the final set 7-5.

Serena Williams or Caroline Wozniacki now await Azarenka in the last four of the tournament.