Sky Sports pundit warns Novak Djokovic after Kevin Anderson win

Roger Federer saw progress into the ATP Tour Finals last four with a 6-4 6-3 win over Kevin Anderson. Sky Sports pundit Greg Rusedski wars, Federer is back. "I thought Federer was excellent tonight,” Rusedski said on Sky Sports. “Tactics were superb. He served better, improved dramatically from his second match again. “He looks like he is back. Never discount a champion. "He will be absolutely delighted to have got his revenge over Kevin Anderson from when they last met at Wimbledon. This was big fro him psychologically as well."

ATP Finals – Friday Schedule: Novak Djokovic vs Cilic, Zverev vs Isner