LONDON, England - Tuesday will see the final eight players in the draw battle it out for a place in the semifinals. Headlining play on Centre Court will be the battle of the former champions between Petra Kvitova and Serena Williams, which will be followed by Sabine Lisicki against Angelique Kerber.
 Serena Williams (USA #6) vs.  Petra Kvitova (CZE #4)
Head-to-head: Williams leads 2-0
Serena Williams' passage to the quarterfinals has certainly not been plain sailing, and with defending champion Petra Kvitova standing in her way next, the journey is unlikely to get any smoother. In her third and fourth round matches, against Zheng Jie and Yaroslava Shvedova, Williams had to summon upon all her reserves of physical and mental energy, scraping by both in three grueling sets.
Kvitova had a scare of her own on Monday; coming from a set and a break down to defeat an inspired Francesca Schiavone. This was in stark contrast to the first three rounds, in which the Czech had barely broken sweat and looked to be approaching the devastating form that took her to last year's title. As one of the few players on tour capable of trading on equal terms with Williams, an on-form Kvitova will believe the match is on her racquet. What makes the encounter all the more intriguing is that Williams is undoubtedly thinking the exact same thing.
 Sabine Lisicki (GER #15) vs.  Angelique Kerber (GER #8)
Head-to-head: Kerber leads 4-0
Sabine Lisicki's preparations for Wimbledon did little to suggest that she would still be around midway through the second week. Arriving at the All-England Club on a five-match losing streak, the German seemed a long way from the form that took her to last year's semifinals, and early round struggles with Bojana Jovanovski and Sloane Stephens did little to convince otherwise.
But with a serve and forehand that few can match, Lisicki is always dangerous. Something Maria Sharapova found out to her cost in the fourth round. Next up is Angelique Kerber. While the edge in power, and SW19 experience, may lie with Lisicki, Kerber, who has won both their 2012 encounters, has the skills to disarm her; Kerber's return has been excellent in the first week - breaking serve at least five times in each round - and she has the court craft to outmaneuver her explosive compatriot.
 Victoria Azarenka (BLR #2) vs. Tamira Paszek (AUT #37)
Head-to-head: Azarenka leads 2-0
Victoria Azarenka sent out a warning shot that echoed round not just the roof-covered Centre Court but also the rest of the All-England Club on Monday when she dismissed Ana Ivanovic for the loss of just one game. And more of the same will be required in the last eight, because, despite their disparity in ranking, Tamira Paszek represents a real danger to the No.2 seed.
For two weeks now, higher-ranked opponents have been waiting for Paszek to run out of steam. However, going by her clinical defeat of Roberta Vinci - her ninth straight win on grass - there is little danger of that. The pair's only previous meeting in the last three years came at the same stage of Wimbledon 12 months ago when Azarenka ran out a comfortable winner.
 Agnieszka Radwanska (POL #3) vs.  Maria Kirilenko (RUS #19)
Head-to-head: Radwanska leads 5-2
Agnieszka Radwanska has gone about her business quietly at this year's Wimbledon, avoiding the drama that has accompanied many of her title rivals' progress. In four matches, the Pole has spent just four and a half hours on court, dropping a meager 16 games in the process.
Almost as impressive has been her quarterfinal foe, Maria Kirilenko, who has yielded just one set in reaching the same stage. The Russian is an accomplished doubles player and has the eclectic game to trouble the best on her day, as evidenced by five career victories over Top 5 players. If she is to make this six, though, she is likely to require a fast start, as Radwanska is a staggering 39-0 this season after winning the first set.