Pat Cash: 'I keep underestimating Novak Djokovic's toughness'

Former Wimbledon champion Pat Cash has praised Novak Djokovic for being able to beat Roger Federer despite the majority of the US Open crowd cheering for his opponent at Flushing Meadows.

The world number one claimed his 10th Grand Slam by sealing a 6-4 5-7 6-4 6-4 triumph in the final in New York.

On Twitter, Cash, who hit out at some of the spectators by branding them "disrespectful", has admitted that he underestimated Djokovic.

He tweeted: "Congrats to #NovakDjokovic I keep underestimating this guys toughness not only beat #Federer but 17,000 fans many v disrespectful."

Djokovic also won the Australian Open and Wimbledon this year.