US OPEN champion Juan Martin del Potro will not be complacent in his search for future grand slam glory, despite landing his first title with a defeat of Roger Federer.

Juan Martin del Potro brought Roger Federer’s five-year dominance at the US Open to an end at Flushing Meadows – and then pledged to work even harder to emulate the world number one.

Five-time champion Roger Federer held off a game challenge from Germany’s Simon Greul to set up a US Open third-round match with Lleyton Hewitt.

ROGER FEDERER has turned to the history books and other sports in his search for new objectives following a fourth consecutive US Open win.