ATP World Tour Finals: Novak Djokovic beats Juan Martin Del Potro at O2 to make semi-finals
By Paul Higham <i>Twitter: <a href=' http://bit.ly/e6TSqR' class='instorylink'>@SkySportsPaulH</a></i>
Thursday 7 November 2013 23:12, UK
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Novak Djokovic delighted with hard-earned win
Novak Djokovic survived a strong challenge from Juan Martin Del Potro to stretch his winning run to 19 matches and book his place in the semi-finals of the ATP World Tour Finals.
