I learned the most from him , and I 'm very grateful to him for that . 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 . He reached semifinals of Australian Open and won an Olympic gold medal in doubles .
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 . He reached semifinals of Australian Open and won an Olympic gold medal in doubles .