It's hard to see this day: Novak Djokovic on Roger Federer's retirement

Novak Djokovic took to Instagram to pen a note on Roger Federer's retirement. He wrote, "Roger...it's hard to see this day and put into words all...we've shared in this sport together." He added, "It's an honour to know you on and off court...and for many more years to come. I know...this new chapter will hold amazing things for you."