DEFENDING champion Serena Williams survived a major scare against Victoria Azarenka to keep her bid for a fifth Australian Open title alive.

The world number one recovered from being a set and a double break behind to overpower her 20-yearold rival 4-6 7-6 (7/4) 6-2 and book her place in the semifinals.

Hopes of an all-Williams match-up in the last-four were dashed, however, after Venus Williams was on the opposite end of an equally impressive comeback from China’s Li Na.

Venus Williams passed up a chance to serve for the match in the second set and was made to pay as she lost a marathon match with the 16th seed 2-6 7-6 (7/4) 7-5 in two hours and 47 minutes.