Russia's Maria Sharapova has reached the Olympic quarter-finals after defeating Sabine Lisicki in a compelling three-set match at Wimbledon.

After a hotly-contested opening seven games, Lisicki was the first to break in the eighth and move 5-3 ahead.

The German could not, however, serve out the set as Sharapova broke straight back and soon the pair were in a tie-break.

Both women had set points before Lisicki came through 10-8 with some gutsy defensive play.

In the second Lisicki was again the first to break, taking a 4-3 lead, but again she couldn't hold onto the advantage as Sharapova broke the German's serve twice in a row to take the set 6-4.

The German underdog broke early in the decider but was broken back straight away before Sharapova made a crucial breakthrough to take a 5-3 lead and serve out the match.

The Russian next faces Belgian veteran Kim Clijsters for a place in the last four.