Serena Williams (1) vs. Sabine Lisicki (23)
In normal circumstances, a match featuring the best serve in the women's game against the second best serve in the women's game would be expected to be really close. However, Serena Williams play in the past year has been several leagues above normal. The world no. 1 doesn't only possess the best serve, but the best game on the WTA Tour altogether. Her movement on grass is so natural and easy, that there is hardly a rally that she doesn't dominate.
Her opponent in the fourth round is Sabine Lisicki, and the German has become a darling with the Wimbledon crowds due to her performances at SW19 over the past few years. With a fantastic serve and booming forehand, grass is clearly Lisicki's most effective surface. Not that it will be of much assistance on Monday. I believe that Lisicki is the one player who is capable of possibly extending a set to a tie-break against Serena. That should pretty much be the extent of her challenge.
Laura Robson vs. Kaia Kanepi
Robson has captured the nation's imagination with her run to the last 16, making her the first female Briton to make it this far since Sam Smith in 1998. Robson is amongst a crop of young women's players who are breaking into the game on the back of a huge serve. Her lefty serve is a considerable advantage when on song, and the top spin she consistently generates off her ground strokes enhance the belief amongst many in the punditocracy that she will eventually crack the top five.
Blocking her path to a possible dream quarter-final against Serena is the streetwise Estonian Kaia Kanepi. Kanepi will be no pushover, herself possessing a fearsome serve. Robson can take advantage of the fact that Kanepi's extremely powerful baseline shots are almost always flat in trajectory, which could lead to several errors against topspin. However, if Robson isn't switched on mentally, Kanepi is equally capable of ruthlessly taking advantage. An interesting battle awaits.
Agnieszka Radwanksa (4) vs. Tsvetana Pironkova
In her third round encounter against Madison Keys, Radwanska proved why she finished runner-up at Wimbledon last year. Clearly playing against an opponent who had more power and pace in her shots, Radwanska showed that guile, good movement and smart placement is still extremely effective in the modern game. In addition, her subtle approach shots and deft touch at net are valuable assets on grass.
Pironkova is also a very capable player on grass, having twice beaten Venus Williams at Wimbledon. One could argue that her game would almost classify as 'Radwanska Lite'. Another player who relies on the wiles of placement and precision rather than power, she can easily frustrate bigger hitters into unforced errors. Despite the low profile of the match, in actuality it is a shot makers dream. Radwanska should prove to have too much, but the Bulgarian is capable of upsetting anyone on her day.
Roberta Vinci (11) vs. Li Na (6)
Other than a titanic affair in the second round against Jana Cepelova in the second round, Vinci has dominated all of her matches at Wimbledon this year. The Italian veteran has had a splendid year and a half since the beginning of 2012. Her doubles expertise has proved handy on grass, enabling her to finish many points by coming forward and executing brilliant volleys.
Grass isn't Li Na's favourite surface, and that she has made it this far already is testament to her tenacity and determination. Li doesn't move easily on grass, yet her accuracy in finding the lines from the baseline, in particular the forehand, can allow her to dictate points. If she gets on a run, Li can win sets in a blink of an eye. This match is an interesting clash of contrasts between Vinci's more classical grass court style and Li's more direct game from the back, and is simply too close to call.
Monica Puig vs. Sloane Stephens (17)
Puig has captured the imagination of many at Wimbledon by reaching the round of 16. After causing a big upset in the first round by easily overcoming fifth seed Sara Errani, the 19 year-old from Puerto Rico has engaged in some tough three-setters, but has allied resilience and quality to come through on the victorious side. She plays with little inhibition, and is equally comfortable with her backhand and forehand.
Sloane Stephens knows what Puig is growing through, announcing her arrival on the big stage by beating Serena in the quarter-finals at the Australian Open. To her credit Stephens has remained grounded, and has impressively maintained consistency, reaching the round of 16 for the third consecutive grand slam. Stephens has also played some close three-setters, but has come through by showing maturity in positions where all looked lost. It is this maturity coupled with a little more experience that should give her the edge over Puig.
Marion Bartoli (15) vs. Karin Knapp
There is no doubt that Bartoli's best surface is grass. One of the few players in the current game, who hits double-handed shots on both wings, Bartoli has a great mix of power and the ability to generate improbable angles. Bartoli might look at the open draw as another opportunity to reach the finals at Wimbledon after 2007.
She is the overwhelming favourite against the unheralded Italian Karin Knapp. Knapp however has already defeated two dangerous opponents en route to the round of 16 - Lucie Safarova in the second round and Maria Sharapova's conqueror, Michelle Larcher de Brito in round three. If Knapp is to add her biggest scalp, it would have to be on the back of an erratic and inconsistent display by Bartoli.
Petra Kvitova (8) vs. Carla Suarez Navarro (19)
While Kvitova is far from the dominant performer that won Wimbledon in 2011, the Czech southpaw has made it to the fourth round on the back of some rarely seen resilience. Her serve has faltered throughout the tournament and there has been no consistency in her ground strokes, alternating between winners and unforced errors. However, she has made it into the second week, and if she can draw from her experience of winning the tournament, she still has the game to reach the final.
Carla Suarez Navarro possesses a single-handed backhand that is extremely elegant and yet very precise. The Spaniard generates spin easily of the backhand, and is equally dangerous down the line or crosscourt. It is a weapon that serves her really well on grass, although a weak serve is a major disadvantage against top opponents. Expect Suarez Navarro to hit some dazzling winners, but Kvitova should be able to hit her way through to the quarterfinals.
Kirsten Flipkens (20) vs. Flavia Pennetta
At every grand slam there is a player in the fourth round of the draw who has sneaked in under the radar. At Wimbledon, it is Kirsten Flipkens. Flipkens hails from the country of Henin and Clijsters, and while she doesn't possess the excellence of her countrywomen, she does know how to play within her limits, and doesn't have any particular weaknesses nor any big weapons.
The beneficiary of Victoria Azarenka's withdrawal in the second round, Pennetta has rode her fair share of luck in getting this far in the tournament. Pennetta doesn't possess the power that she had when breaking into the top 10 in 2009. However, she still has remarkable endurance levels, and will never give an easy point to her opponents. In a match that will feature many long and consistent rallies, the result will probably come down to who blinks first in a close match.