The contest looked like it was going to be a tight affair as it featured three service breaks at the start but Del Potro - a former world number four who is currently ranked 46th after missing most of last year with a wrist injury - took control and closed the set with an ace.

It was the 23-year-old Serb's fifth title this year, after he captured the Australian Open, the Dubai Championships as well as Masters series events in Indian Wells and Miami.