Fifth-ranked Fritz triumphed 6-3, 3-6, 7-6 (7/3) over world number two Zverev in a thrilling match at the season-ending event in Turin.

Fifteen years after famously stunning Pete Sampras at Wimbledon, seven-time champion Roger Federer returns to the All England Club with his career at a crossroads and his confidence at crisis point.

Novak Djokovic and Roger Federer are poised to become the first $100 million men in tennis in 2016, in a gripping sub-plot to the new Grand Slam season.