Nadal secures year-end world number one spot

LONDON (Reuters) - Spain's Rafael Nadal will end the year ranked number one in the world rankings for the third time in his career after beating Switzerland's Stanislas Wawrinka 7-6(5) 7-6(6) at the ATP World Tour Finals on Wednesday.

The 27-year-old's second Group A victory at the season finale means he cannot be overtaken by chief rival Novak Djokovic even if the Serb retains his title in London. Nadal's hard-fought win also guaranteed his place in the semi-finals.

(Writing by Martyn Herman; Editing by Ken Ferris)