Tennis-Federer swats aside Wawrinka to set up Djokovic final

LONDON, Nov 21 (Reuters) - Roger Federer set up a showdown with Novak Djokovic when he beat fellow Swiss Stanislas Wawrinka 7-5 6-3 in their semi-final at the ATP World Tour Finals at the O2 Arena on Saturday. The 34-year-old six-times champion fell 4-2 behind in the opening set but rattled off four consecutive games to move ahead and cruised through the second set with smooth efficiency. Wawrinka saved a match point at 2-5 but 17-times grand slam champion Federer closed out victory in little more than an hour. World number three Federer, who won all his group matches this week, has reached the final of the year-ender for the 10th time but has not won the title since 2011. Last year, when he also beat Wawrinka in a gruelling semi-final, he conceded the final to Djokovic with a back strain. Four-times champion Djokovic beat Rafael Nadal 6-3 6-3 in the day's first semi-final. (Reporting by Martyn Herman, Editing by Ian Chadband)