Serena sets up Dementieva clash

The two-time champion needed just a little over an hour to see off the promising 19-year-old to set up a meeting with Elena Dementieva and ensure that both of Thursday's semi-finals will be American-Russian affairs, with older sister Venus facing top seed Dinara Safina.

Venus, who had already booked her place in the semi-finals, watched her sister produce an error-free first set to draw first blood against Azarenka and although Serena dropped her serve in the second set, she recovered and has reached the semi-finals without dropping a set.

The American made light of the searing heat to produce a running forehand in the third game and then out-hit her young opponent to gain the first break to lead 4-2.

She consolidated the break with a two-handed backhand struck through gritted teeth and raised her game yet further to break once more to take the set in just 26 minutes.

The Arizona-based Azarenka briefly upped her game in the second set to suggest her straight-sets victory over Williams in Miami earlier this year was no fluke.

She threatened to strike back in the opening game of the second set, successfully challenging a baseline call to force her first break points of the match, but Williams simply produced three booming serves to avert the danger.

There was a rare moment of alarm for the American when she went over on her ankle in a baseline tumble but quickly got back on her feet to force a break point.

The 19-year-old had to dig deep to hold her serve in the fourth game after coming up with two double faults, and then pounced on a series of second serves from Williams to achieve the first break of the second set.

The response was typical as Williams broke back immediately, held to love and then broke the teenager again before serving for the match.