Djokovic tops Nadal at ATP World Finals

LONDON, Nov. 27 (UPI) -- Novak Djokovic beat Rafael Nadal in straight sets Friday, staying alive at the season-ending ATP World Finals in London.

Djokovic will take the final spot in Saturday's tournament semifinals if Nikolay Davydenko loses to Robin Soderling in a late Friday match. Soderling has wrapped first place in Group B and will go against fifth-seeded Juan Martin del Potro in the semis. World No. 1 Roger Federer faces either Djokovic or Davydenko in the other semifinal.

Djokovic posted a 7-6 (7-5), 6-3 win over Nadal. A seesaw first set -- each player dropped serve twice -- saw Djokovic move out to a 6-2 lead in the tiebreaker but Nadal won three straight points before Djokovic took the set.

Nadal, who had 35 unforced errors Friday, needed medical treatment for a back problem three games into the second set and Djokovic became more aggressive, taking control with a fourth game break.

Nadal entered the tournament with a chance to overtake Federer for the top spot in the ATP rankings but didn't win a set in finishing round-robin play 0-3. He could drop to No. 3 in the world should Djokovic repeat as the World Finals champion.