Beaten Federer won't obsess with winning 18th Grand Slam title

Roger Federer insists he will keep playing into 2015 but will not become obsessed over winning an 18th Grand Slam title, a target which is slipping further and further away.

The 33-year-old Swiss was knocked out of the US Open semifinals in straight sets by Marin Cilic, the world No 16 on Saturday, a loss which extended his failure to reach a final in New York to five years.

It is a long stretch of disappointment for a man who won five successive titles between 2004 and 2008 but whose last appearance in the championship match was in 2009 when he was upstaged by Juan Martin del Potro.