German seventh seed Angelique Kerber has edged out Venus Williams to take a place in the quarter-finals of the women's Olympic singles at the All England Club.
Both players dropped serve twice in the first set and it looked as if Kerber was going to lose the tie-break when she found herself 5-1 down.
However, the German snatched the next six consecutive points to win 7-5.
After having an early break cancelled out in the second, Williams had chances to seize control but failed to take another break point.
Instead, Kerber went on to win the second tie-break 7-5 again and make the last eight of the competition.
The seventh seed will take on world number one Victoria Azarenka in the next round.
