As a golden tennis era transitions into its next guise, when, how, and why to retire is one of the biggest questions in the sport.

Roger Federer feels his opinions of tennis foes Novak Djokovic and Rafael Nadal were clouded by the intense rivalries they shared.

4 into his 95th Masters 1000 quarter-final. The Serb battled against the young Czech Jakub Mensik and prevailed 6-7, 6-1, 6-4 in two hours and 19 minutes. Djokovic dropped a tight opener and stayed composed, serving well in sets two and three en route to his ninth Shanghai Masters semi-final.