Wimbledon: Monday 23 June to Sunday 6 July Coverage: BBC TV, BBCi, Radio 5 Live and the BBC Sport website.
Williams is bidding to reach her seventh final at the All England Club
Defending champion Venus Williams produced a convincing display to overwhelm Maria Jose Martinez Sanchez and reach round four of Wimbledon.
The four-time champion powered her way through the first set in just 25 minutes and broke at 5-5 in the second to wrap up a 6-1 7-5 victory.
Williams now faces 18-year-old Russian Alisa Kleybanova and is joined in the last 16 by Elena Dementieva.
Fifth-seed Dementieva 7-6 (7-2) 7-5 will play Israel's Shahar Peer.
Peer, seeded 22, emerged triumphant after three hours and 25 minutes against ninth seed Dinara Safina.
French Open runner-up Safina was broken at 5-6 to concede the first set but, after saving match point at 4-5 down, snatched the second on a tie-break.
Suffering from a thigh injury that required extensive treatment, the Russian repeatedly lost her temper and was forced to save a second set point at 5-6 before double faulting to hand Peer a 7-5 6-7 (4-7) 8-6 victory.
Dementieva struggled to find any sort of consistency early on against Argentina's Gisela Dulko, who had benefited from walkover against the injured Lindsay Davenport in round two.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.