The Swiss, who has already won the Australian Open and Indian Wells so far this year, extended his win streak over Berdych to seven matches.

There was plenty of tension in the match-deciding tie-breaker, where Federer saved match point and then Berdych lost on a double-fault.

Federer next will play the winner of Thursday's later quarter-final between two of the ATP's up and coming stars, Australia's Nick Kyrgios and Germany's Alexander Zverev.

Spain's Rafael Nadal and Italy's Fabio Fognini are already through to Friday's other semi-final.