Federer hit with first slam fine in more than a decade

He's the most unflappable man in tennis. But even Roger Federer loses his cool sometimes.

That happened during his extraordinary five-set comeback win over Tennys Sandgren on Tuesday, when he chastised himself in his native tongue during the third set - and was overheard by a multi-lingual linesperson.

He was hit with a code violation during the match, which led to a terse conversation with chair umpire Marijana Veljovic.

It also resulted in just the second fine of Federer's extraordinary career - a $4400 whack for the audible obscenity.

It's just the second time Federer has been fined at a grand slam and the first in more than a decade.

In 2009 he was penalised for swearing during his defeat to Juan Martin del Potro.