Federer flays Blake

Roger Federer fired his way into the semi-finals of the Nasdaq-100 Open on Thursday in Miami but Andy Roddick ran out of firepower and women's world number one Amelie Mauresmo fired blanks.

Maria Sharapova advanced to the final after her French opponent Tatiana Golovin was forced to retire due to an ankle injury.

Federer swept past James Blake for the second time in a month with a 7-6 6-4 win for his 46th straight victory on US soil and 25th consecutive victory against an American player.

"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 Spain's David Ferrer, who pulled off a 6-3 4-6 6-4 upset of Andy Roddick to prolong the American's career crisis.

Roddick last won a title in October.

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 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... but I believed in myself, I did my job."

Kuznetsova will face Sharapova in the final after her semi-final opponent Golovin rolled her ankle and had to retire from an enthralling contest.

Sharapova took the first set 6-3 but the French teenager battled back to take the second 7-6. The 18-year-old was then forced to retire in obvious pain with Sharapova leading 4-3 in the third.