Nicolas Kiefer retires from professional tennis at the age of 33 . However , after suffering a wrist injury that year , the player tipped to follow in the footsteps of six-time major winner Becker has struggled to get back to the top of the game , playing on the lowly Challenger Tour and slipping to a world ranking of just 722 . Former world number four wants to spend more time with his partner and baby daughter . German is currently ranked 722 after suffering wrist problems over the last couple of years . TL;DR
Nicolas Kiefer retires from professional tennis at the age of 33 . Former world number four wants to spend more time with his partner and baby daughter . German is currently ranked 722 after suffering wrist problems over the last couple of years . TL;DR