Halep, Wozniacki lead the pack

With Serena out, Australian Open crown is anyone's

MELBOURNE - Simona Halep and Caroline Wozniacki spearhead the charge to succeed Serena Williams at an Australian Open left wide open by the withdrawal of the defending champ and new mom.

A pregnant Williams sealed her 23rd Grand Slam singles title and seventh Melbourne Park crown a year ago, but last week announced she wouldn't defend her title, saying she was "super close" but not quite ready to compete after giving birth in September.