Juan Martin del Potro beats Roger Federer to claim semifinal place in ATP World Tour Finals . The Spaniard will face world number one Ferrer finishes on a high note as he beats Janko Tipsarevic in final round-robin match . `` I had a good feeling going into the match , definitely the right game plan . Federer will face Andy Murray in Sunday 's semifinals , while Del Potro plays Novak Djokovic .
Juan Martin del Potro beats Roger Federer to claim semifinal place in ATP World Tour Finals . The Spaniard will face world number one Ferrer finishes on a high note as he beats Janko Tipsarevic in final round-robin match . Federer will face Andy Murray in Sunday 's semifinals , while Del Potro plays Novak Djokovic .