Venus beats sister Serena to set up Sharapova semi

Venus Williams beat her sister Serena for the first time in three-and-a-half years on Tuesday, sealing a place in the semi-finals of the Nasdaq-100 Open with a 6-1 7-6 win.

Venus brought to an end her sister's three-year reign as women's champion in Miami and will play Wimbledon champion Maria Sharapova in the last four.

"We've played some huge matches," said Venus. "This one definitely is a highlight."

Venus raced to a 5-0 lead in the first set and always looked the stronger but Serena fought back in the second and had two set-points in the decisive tiebreaker before her sister wrapped the match up.

"There was nothing I could do in the first set but I had plenty of chances in the second," said Serena.

Sharapova beat former world number one Justine Henin-Hardenne 6-1 6-7 6-2 in her quarter-final to end the Belgian's comeback run.

In the men's draw, six-times champion Andre Agassi went through to the last eight after beating French Open champion Gaston Gaudio 7-6 6-2.

Agassi will play Taylor Dent in the quarter-finals after the American beat German Florian Mayer 6-3 6-4.

Top seed Roger Federer survived a stiff fourth round test from Mario Ancic, eventually beating the Croatian 6-3 4-6 6-4 to record his 29th win of the season.

The Swiss has lost just one match since last August and next plays Tim Henman after the sixth seeded Briton beat Czech Radek Stepanek 7-5 6-3.