Victoria Azarenka (Blr), 26, ranked 16th
Best Open result: Champion (2012,2013)
The most likely contender to upset Serena Williams' dominance, Azarenka is the second favourite behind the American despite her seeding of No. 14.
She stormed her way to a second Brisbane International crown last week without dropping a set - her first title since she beat Williams in Cincinnati in 2013 and following a two-year spell of injury problems.
With the top women players racked by injury and illness, the Belarusian's resurgence could not have come at a better time.
Williams has a 17-3 career head-to-head advantage over Azarenka, but all three of Azarenka's wins came in finals, albeit non-Grand Slam tournaments.
Garbine Muguruza (Esp), 22, ranked 3rd
Best Open result: Fourth round (2014, 2015)
The young Spaniard was last year's break-out star. She started the year at what was then her career high ranking of No. 21, but stormed to third by year-end, making her first Grand Slam final at Wimbledon.
The last time anyone had such a rapid ascent was two-time Wimbledon winner Petra Kvitova in 2011.
Muguruza has said that learning to remain cool in tough situations has been pivotal to the improvements in her game.
Svetlana Kuznetsova (Rus), 30, ranked 25th
Best Open result: Quarter-finals (2005, 2009, 2013)
If Azarenka is making a comeback, then Kuznetsova is enjoying a renaissance - just do not tell the veteran that.
She rolled back the years with a 6-0, 6-2 rout of Monica Puig to claim her 16th title at the Sydney International last week. She then denied returning to the women's elite, insisting she never left.
Said the two-time Grand Slam champion: "I don't think I left somewhere, or I've been lazy, or I didn't work. I still was here, still doing the same tournaments. Just didn't go my way."
Known for her fighting spirit, heavy forehand and movement on court, the No. 23 seed might just have it her way this fortnight.