BERLIN (AP) Nicolas Kiefer retired from tennis Thursday after a career in which the German reached a No. 4 ranking and the semifinals of the 2006 Australian Open.

The 33-year-old Kiefer said on his website he wants to spend more time with daughter Mabelle Emilienne, who was born in August.

Kiefer won six tournaments during his career and ascended to the No. 4 ranking in 2000. He played for Germany in the Davis Cup and teamed with Rainer Schuettler for a doubles silver medal at the 2004 Athens Olympics.