Federer swept past James Blake for the second time in a month with a 7-6 6-4 win for his 46th straight win on U S soil and 25th consecutive victory against an American player yesterday.
''There were tough conditions and I handled them well,'' Federer told reporters, referring to the swirling wind.
The Swiss world number one will next face David Ferrer.
Spain's Ferrer pulled off a 6-3 4-6 6-4 upset of Andy Roddick, to prolong the career crisis of the former world number one who last won a title in October.
''I'm on the verge of playing really good tennis again,'' Roddick told reporters. ''Parts of my game were really good at times throughout this whole tournament.
''It's just a matter of trying to kind of take one from here, take one from here, and kind of put them together. I feel a lot better leaving this tournament than I did leaving the last tournament.'' MAURESMO HAMMERED Mauresmo's bid to reach the Miami final disintegrated as she was hammered 6-1 6-4 in the semis by Russian Svetlana Kuznetsova.
Kuznetsova, the 2004 U S Open champion, earned her second victory in a month over the Frenchwoman following her success in Dubai.
She will face either fellow Russian and fourth seed Maria Sharapova or Moscow-born French teenager Tatiana Golovin in the final.
Kuznetsova capitalised on 29 unforced errors from the Australian Open champion, who was erratic throughout the 78-minute contest.
She struck 33 winners and denied Mauresmo three second-set break chances as the top seed struggled to get into the contest.
Mauresmo saved two match points before suffering only her fourth defeat of the season.
''Dubai gave me a lot of confidence,'' Kuznetsova told reporters after narrowing Mauresmo's head-to-head advantage to 4-2.
''I started well, hung in and had my chances. I'm very excited with how I played today. I was a bit nervous. But I believed in myself, I did my job.'' REUTERS PM BST0932