Roger Federer, the world number two, defeated American Andy Roddick 6-3, 4-6, 6-4 Wednesday to set up a semi-final meeting with Serbian Novak Djokovic at the Sony Ericsson Open.
Third seed Djokovic produced sparkling tennis to beat Frenchman Jo-Wilfried Tsonga 6-3, 6-4 but will now have a major test in his bid to reach the final.
In a tight third set, dominated by serve, a stroke of luck set up Federer for the match point when a pass popped up off the net and beat Roddick.
The Swiss won the decisive point and while it was hard on Roddick it was Federer's consistency throughout that paid off for him.
The 13-time Grand Slam winner will have to be on top of his game again Friday as his opponent Djokovic is showing signs of a real return to top form.
Delivering dashing groundstrokes and generating plenty of spin on his second serves, the Serb was on top throughout.
Tsonga had a chance to extend the second set but failed to convert two break points at 5-4 and in the end Djokovic wrapped up victory with an emphatic smash which brought roars from noisy Serbian supporters.