Roger Federer: "Rough" semi-final ahead

Roger Federer has conceded that he has no preference with regards to whom he will face in the semi-finals of the ATP World Tour Finals.

The former world number one had already booked his place in the last four of the competition ahead of his 7-5 4-6 6-4 victory over Kei Nishikori earlier today.

He will now take on either Rafael Nadal, Andy Murray or Stanislas Wawrinka for a place in Sunday evening's final and when asked which of that trio he would rather come up against, Federer admitted that it would be "rough either way".

"Rafa, Andy or Stan - it is gong to be rough either way in the semi-finals. Regardless, I'm looking forward to it," he said during his post-match interview.

On the seven previous occasions that 34-year-old Federer has won each of his three group games at the season-ending event, the Basel-born player has gone on to at least reach the final.