Wimbledon: Monday 23 June to Sunday 6 July
Coverage: BBC TV, BBCi, Radio 5 Live and the BBC Sport website.
Radwanska won the girls' singles title at Wimbledon in 2005
Agnieszka Radwanska kept her composure to come from a break down in the final set and send fourth seed Svetlana Kuznetsova crashing out of Wimbledon.
The 19-year-old Pole, seeded 14, broke at 5-3 and 5-5 in the decider before serving out for a 6-4 1-6 7-5 triumph.
Kuznetsova's defeat ensures that for the first time in history, none of the top four women's seeds have reached the last eight at the All England Club.
Radwanska now faces sixth seed Serena Williams for a place in the last four.
The pair have met once previously with Williams winning 6-3 6-1 on clay in Berlin.
But Radwanska, who lifted the Eastbourne title before arriving at SW19, will be full of confidence after beating world number four Kuznetsova, a feat she also achieved at the Australian Open in January.
"I'm very happy to reach the quarter-finals for the first time," Radwanska, the girls' singles champion in 2005, told BBC Sport.
I was suffering so much in my first match. Everybody needs rest. The season is too long
"Svetlana was playing unbelievable tennis and serving very well but I stayed with her until the end.
"I didn't want to give up at this stage of a Grand Slam and in the end I did it."
Kuznetsova netted an attempted passing shot to concede a break in the eighth game of the first set and, although the 23-year-old hit back immediately, Radwanska converted the third of three set points with a stunning backhand down the line.
Former US Open champion Kuznetsova stormed into a 4-0 lead in the second set and, after saving three set points at 5-1 down, Radwanska succumbed when sending a forehand wide.
Continuing her dominance from the second set, Kuznetsova moved 4-1 ahead in the third before Radwanska launched her match-winning comeback.
Kuznetsova believes the players need more time to get acclimatised to grass before Wimbledon.
She said: "The grass court is very tough to get used to and nobody has time after the French Open.
Vaidisova now comes up against Zheng Jie for a place in the semi-finals
"It's extremely tough. I was suffering so much in my first match. Everybody needs rest. The season is too long.
"You go through fighting or have a bit of luck, so I think it's because of this that everybody's out."
The top seed left in the draw is number five Elena Dementieva, the Russian destroying Israel's Shahar Peer, who beat French Open finalist Dinara Safina in a marathon third-round match, 6-2 6-1.
China's Zheng Jie, meanwhile, became the first ever women's wildcard to reach the Wimbledon quarter-finals with a convincing victory over 15th seed Agnes Szavay.
The 24-year-old, ranked 133 in the world, broke Szavay once in the first set and then twice in the second having been a break down.
Zheng, who stunned world number one Ana Ivanovic in round three on Friday, won 6-3 6-4 in an hour and 21 minutes.
She is only the second Chinese player to reach the last eight at Wimbledon, equalling Li Na's achievement in 2006.
The doubles specialist was the second lowest ranked woman left in the women's singles draw but looked at home in only her second Grand Slam last 16 appearance.
Only two female players in Grand Slam history have reached the last eight on a wildcard, Mary Pierce at the 2002 French Open and Martina Hingis at the 2006 Australian Open.
In the last eight Zheng plays Nicole Vaidisova, who beat Anna Chakvetadze.
Vaidisova overcame an indifferent start to dominate eighth seed Chakvetadza and secure her second successive quarter-final at the All England Club.
The Czech, seeded 18, excelled as Russia's Chakvetadze failed to control her emotions or live up to her seeding and was beaten 6-4 6-7 (0-7) 3-6.
Nadia Petrova ended Alla Kudryavtseva's surprise run at SW19 with a 6-1 6-4 win.
Kudryavtseva, another Russian, defied her world ranking of 154 to beat Maria Sharapova in round three but was easily swept aside by her compatriot.