Defending champion Novak Djokovic set up a title showdown against Rafa Nadal at the ATP World Tour Finals with a 6-3 6-3 defeat of Switzerland's Stanislas Wawrinka on Sunday. The Serb, who lost his number one ranking to Nadal in October, was too solid for Wawrinka in the day's second semi-final as he racked up a 14th consecutive victory over the 28-year-old. Djokovic used all his defensive skills in the eighth game of the first set to convert a break point for a 5-3 lead and took the opener with an ace. Wawrinka, who has made the semi-finals on his debut appearance at the season-ending showpiece, hung on grimly in the second set after dropping serve but Djokovic was clinical as he stretched his winning streak to 21 matches. Click here to read full news..