Novak Djokovic plays home favourite Mardy Fish in the US Open fourth round later today.

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The time has come for Fish to stand up and be counted in a major. The American has always underperformed in the slams and this is the sort of match he needs to win if he's going to achieve his dream of challenging  for one of the game's biggest titles. Fish has been in fine form all summer, winning Atlanta and making the Cincinnati final but this is where it matters for him, where all the hard yards he's put in on his  fitness need to pay off.

Djokovic has not failed to reach the semi-finals in New York since 2006 and he will take some beating. James Blake thought he had a shot but the Serb overwhelmed him with ease in front of a raucous home crowd on Saturday night.

Both men have been the distance so far in this tournament. Fish has twice battled through five sets, in round one against Jan Hajek and then he thrilled the crowd by coming through a third round classic against Arnaud Clement.

Fish is going to have to serve out of his mind and nail his approach shots as while he's not going to win this one from the baseline, Djokovic has some of the most accurate passing shots on tour particularly off his backhand side. Even though Fish has put a huge amount of fitness work in, Djokovic is still the better mover and if he can pin Fish to the back of the court he can attack that sometimes erratic forehand. 

If it goes five sets then Fish is probably more likely to hold his nerve but our prediction is Djokovic to progress in four. 

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