New Delhi, July 9 -- 20-time Grand Slam champion Roger Federer has admitted that he is inching closer to his retirement from tennis, but stressed that he will miss the game a lot once his illustrious career comes to an end.The Swiss tennis maestro, who is all set to turn 39 next month, continues to remain one of the top players of the ATP tour and is still capable of winning big tournaments World No.4 Federer's only appearance this year came at the Australian Open, where he made it to the semi-final of the Grand Slam tournament before losing to Serbian star Novak Djokovic in straight sets.Federer also holds the record of most major titles with 20 Grand Slam victories in his account and has also spent almost 310 weeks atop of the men's singl...