LONDON — Rafa Nadal may have left the stage but the smooth progress into Wimbledon's second week of the remaining members of tennis's established powerbase suggests further upsets are unlikely in the men's last 16 Monday. The ‘Big Four' have been whittled down to a top three, but for Novak Djokovic, Roger Federer and Andy Murray, who were largely untroubled in their opening matches, there seems no end on the horizon to their dominance at the All England Club. The trio, along with Nadal, have had a monopoly on the Wimbledon title after Lleyton Hewitt beat David Nalbandian to lift the Challenge Cup trophy in 2002. On the evidence of the first week, only Stan Wawrinka, winner of two of the last six majors including last month's French Open, looks capable of stealing a march on the top three. The hard work of maintaining promising starts, however, is likely to begin with more testing encounters Monday. The relentless retriever Djokovic faces the towering figure of Kevin Anderson, Federer's quest for a record eighth Wimbledon title continues against Spaniard Roberto Bautista Agut and Murray faces the huge-serving Ivo Karlovic. Having cruised into the last 16 without dropping a set, world No. 1 Djokovic's renowned return will be tested by the serving of Anderson, whose recent form has prompted a surge up the rankings to a career-high 14. The Serb's elastic-limbed defense has been untroubled in his three opening skirmishes, yet Anderson has weapons and can test the best if they are not on their game. Murray, champion in 2013, has suffered a couple of wobbles in matches against Mikhail Kukushkin and Andreas Seppi, but has looked comfortable enough not be unduly worried by 23rd seed Karlovic. As for fourth seed Wawrinka, the Swiss has made a habit of scything through the early undergrowth of grand slams almost unnoticed and with his majestic backhand should have too much for Belgian David Goffin. In the women's section, Serena and Venus Williams clash in the last 16 on Monday, while Maria Sharapova and Caroline Wozniacki will fancy their title chances as two of the four top 10 players still standing. The 26th clash between the Williams sisters, who have won the Wimbledon title five times each over the last 15 years, will be the first at the All England Club since the 2009 final. And with either world No. 1 Serena or 16th-seeded Venus certain to fall, the second week at Wimbledon is looking appetising for the other silverware contenders in southwest London. Serena, Sharapova, Wozniacki and Lucie Safarova are the only top 10 seeds remaining in the draw after defending champion Petra Kvitova, Simona Halep, Ana Ivanovic, Ekaterina Makarova, Carla Suarez Navarro and Angelique Kerber all failed to get past the first week. While one of the Williams sisters could face Sharapova or Safarova in the semifinals — both face unseeded opposition Monday — Wozniacki cannot meet any of them before the final and only has lower-ranked players in her way. Fourth seed Sharapova, a five-time Grand Slam champion, faces Zarina Diyas of Kazakhstan for a spot in the quarterfinals. Danish fifth seed Wozniacki is the biggest name remaining in her half of the draw and the former world No. 1 faces Spanish 20th seed Garbine Muguruza in the fourth round. The dearth of remaining top 10 players means sixth seed Lucie Safarova, who ghosted through the first week, is now also looking like a serious contender. Last month's French Open runner-up, the Czech reached the Wimbledon semis last year and faces Coco Vandeweghe, the US world No. 47. Another former world No. 1, Jelena Jankovic, is hungry for more after knocking out Kvitova. She faces Agnieszka Radwanska, the 2012 beaten Wimbledon finalist. Victoria Azarenka, the 2012 and 2013 Australian Open champion, has made the Wimbledon semifinals twice but the Belarusian 24th seed could face a rough ride against in-form Belinda Bencic. Fellow Swiss Timea Bacsinszky reached her first Grand Slam semi-final at the French Open last month and the 15th seed is favorite to beat world number 48 Monica Niculescu of Romania. Olga Govortsova is the only qualifier to reach the last 16. The Belarusian faces US 21st seed Madison Keys. — Agencies
