Roger Federer give Novak Djokovic a 'little star' for being top of the class

Roger Federer believes the ’big four’ of men’s tennis is still going strong but admits Novak Djokovic is in a class of his own ahead of next week’s Australian Open.

Djokovic, Federer, Andy Murray and Rafael Nadal – together with the more recent addition of Stan Wawrinka – have long dominated the major tournaments, with only one of the last 24 grand slam champions coming from outside that group.