• Defending champion Roger Federer beat David Ferrer for the 14th successive time to reach the semi-finals of the Barclays ATP World Tour Finals.
  • Leander Paes and Radek Stepanek celebrate their win in the doubles over Marcel Granollers and Marc Lopez in the first match of the day.
  • The stars were out in force to see the singles action with former Bolton footballer Fabrice Muamba at courtside.
  • Chelsea's Juan Mata was also there ...
  • As was actor Sir Ian McKellen.
  • Ferrer entered the O2 Arena as a huge underdog against an in-form Federer.
  • Ferrer battled hard as always, but lost the first set 6-4.
  • Federer had to work harder in the second set and was taken to a tie-break, but won it 7-5 to seal his place in the last four.
  • The Swiss remains on course for a third successive title.
  • Jean-Julien Rojer and Aisam-Ul Haq are still without a victory in the doubles.
  • They lost 7-5 6-4 to top seeds Bob and Mike Bryan.
  • Juan Martin Del Potro took on Janko Tipsarevic in the final game of the night, with both players looking for their first win.
  • Manchester City striker Sergio Aguero was at courtside to watch fellow Argentine Del Potro in action.
  • Del Potro made the perfect start with a bagel first set - 6-0!
  • Tipsarevic got off the mark in the second set but could not prevent Del Potro winning it 6-4.
  • Del Potro boosted his chances of making the semi-finals.
  • An added treat for the O2 Arena crowd saw Del Potro play his second game of the night ...
  • With his opponent being good friend Sergio Aguero!

ATP World Tour Finals - Day 4

Defending champion Roger Federer beat David Ferrer for the 14th successive time to reach the semi-finals of the Barclays ATP World Tour Finals.