Ivanovic retirement puts Venus through

Third seed Venus Williams booked her place in the quarter-finals at Wimbledon today after Serbian 13th seed Ana Ivanovic retired injured in their fourth-round clash.

Venus, chasing her third straight title here and sixth overall, was making a mockery of Ivanovic's former world number one ranking by storming to the first set 6-1 when the Serb called for the trainer in the opening game of the second.

Former French Open champion Ivanovic received treatment to her hip and then held her serve to go 1-0 up in the second before tearfully informing the umpire she could not carry on. Williams will play Polish 11th seed Agnieszka Radwanska for a place in the semi-finals.

Meanwhile, second seed Serena Williams wasted little time in joining sister Venus in the quarter-finals with a 6-3 6-1 demolition of unseeded Slovak Daniela Hantuchova.

Serena, a two-time champion here and the reigning Australian Open champion, never looked in any danger as her superior power in all departments gave Hantuchova minimal options.

She raced to the opening set in just 30 minutes before Hatuchova's game folded completely in the second and she clinched victory after just 56 minutes when the Slovak sent a forehand on the run wide.

She will play Victoria Azarenka, the eighth seed from Belarus, for a place in the semi-finals.

Elsewhere, Victoria Azarenka from Belarus battled her way into the Wimbledon quarter-finals with a hard-fought 7-6 2-6 6-3 victory over Russia's Nadia Petrova.

The eighth seed, the first woman from Belarus to reach the last eight at Wimbledon since Natasha Zvereva in 1998, will have to raise her game to stand a chance against Serena Williams in the last eight.

An abysmal first set was awash with unforced errors, both players each losing their serve three times apiece before Azarenka, yowling with effort on every point, squeaked home 7-5 in a tight tiebreak.

Petrova, treated at the end of the set with ice packs to counteract the heat, came back with all guns blazing to level the match but could not maintain the pressure in the decider and Azarenka wrapped it up after two hours and 25 minutes.

Earlier, Olympic champion Elena Dementieva became the first player to book a place in the quarter-finals when she cruised past fellow Russian Elena Vesnina 6-1 6-3.

The fourth seed reached the last eight for the second year in a row at the All England Club after displaying superior shot range and court coverage to world number 37 Vesnina, whom she has now beaten in all three of their career meetings.

Dementieva cruised through the first in 29 minutes without Vesnina getting close to a break point, and duly polished off the second set when Vesnina sent a backhand volley long after an hour and 10 minutes. She will play French 26th seed Virginie Razzano or Italy's Francesca Schiavone for a place in the semi-finals.