Defending champion Novak Djokovic and six-time winner Roger Federer were once again set on a Grand Slam collision course when they were placed in the same half of the Wimbledon draw.

London – Defending champion Novak Djokovic and six-time winner Roger Federer were once again set on a Grand Slam collision course when they were placed in the same half of the Wimbledon draw on Friday.

World No 1 Djokovic, who swept past Federer in straight sets in the French Open semifinals earlier this month, could meet the Swiss again in the last four.

The top-seeded Serb will start his campaign against Spain's former world number one Juan Carlos Ferrero with Czech sixth seed Tomas Berdych, the 2010 runner-up, a potential quarterfinal opponent.

Federer, who has lost in the quarterfinals in the last two years, takes on another Spaniard, Albert Ramos.

The third seeded Federer, still one title shy of Pete Sampras's record of seven at the All England Club, is scheduled to face Serb eighth seed Janko Tipsarevic in the last eight.

Tipsarevic starts against 2002 runner-up David Nalbandian, the Argentine who was defaulted in last week's Queen's final for accidentally injuring a line judge.

Second seed Rafael Nadal, the 2008 and 2010 champion, and fresh from a record seventh French Open title, meets Brazil's Thomaz Bellucci.

Fourth-seeded Briton Andy Murray, who has lost in the semifinals in the last two years to Nadal, is scheduled to meet the Spaniard again in the last four, but first he must get past wily Russian Nikolay Davydenko in his opener.

Murray has lost all three grasscourt matches he has played this summer and has a minefield of a draw with Spain's David Ferrer, who beat him in the French Open quarter-finals, a potential last eight opponent.

Juan Martin del Potro, the 2009 US Open champion, Queen's winner Marin Cilic, three-time runner-up Andy Roddick and big-serving Canadian Milos Raonic are all in the Scot's section of the draw.

Wildcard Lleyton Hewitt, the 2002 champion but now ranked at 202 in the world, begins against French fifth seed Jo-Wilfried Tsonga, who knocked out Federer in five sets in the quarter-finals last year.

Hewitt's Australian compatriot Bernard Tomic starts against Belgium's David Goffin who went through qualifying at the French Open and reached the fourth round where he took a set off Federer before losing in four.

The draw also threw up the intriguing possibility of a second round clash between America's John Isner and Nicolas Mahut of France, two years after the pair played out the longest match in tennis history at Wimbledon.

Isner won that day, taking 11 hours and five minutes, spread over three days, to triumph 6-4, 3-6, 6-7 (7/9), 7-6 (7/3), 70-68.

In the women's draw, top seed Maria Sharapova, the 2004 champion and this year's French Open winner, begins against Australia's Russian-born Anastasia Rodionova.

Sharapova has beaten Rodionova four times in four meetings without dropping a set.

Unseeded Kim Clijsters, a four-time Grand Slam title winner who will retire after the US Open, is in the same quarter as the Russian and begins against fellow former world number one Jelena Jankovic.

China's number one Li Na, beaten in the second round by Sabine Lisicki 12 months ago, tackles Russia's Ksenia Pervak in the first round.

Defending champion Petra Kvitova of the Czech Republic, the fourth seed, starts her campaign agianst Akgul Amanmuradova of Uzbekistan.

Five-time champion Venus Williams, unseeded this year, takes on Russia's Elena Vesnina while sister Serena, a four-time winner, faces Barbora Zahlavova Strycova of the Czech Republic.

Second seeded Victoria Azarenka, the Australian Open champion, could face Kvitova in the semi-finals, but first the Belarussian takes on America's Irina Falconi. – Sapa-AFP