The race to earn a spot in this year's season-ending WTA Finals in Singapore - or the 'Road to Singapore' - will begin this week, with three tournaments across Asia Pacific marking the start of the 2015 professional women's tennis tour.

The Brisbane International in Australia, Shenzhen Open in China and the ASB Classic in Auckland are the first events on the Women's Tennis Association (WTA)'s 2015 calendar.

There are 54 events and four Grand Slams travelling through 33 countries on the WTA professional circuit this year, before culminating in the prestigious Finals in Singapore from Oct 23-Nov 1.

Serena Williams won the singles crown during the inaugural edition in Singapore last October. The Republic is the first city in Asia-Pacific to host the US$6.5 million (S$8.65 million) event, and will do so for four more years.

Said Williams, the world No. 1: "I am excited for the 2015 season to get started. I was able to end last year on a high note by lifting the Billie Jean King Trophy at the WTA Finals and I have been working hard this off-season to prepare for another season. As women's tennis continues to grow globally, I look forward to seeing all our fans on the Road to Singapore."

Added Stacey Allaster, WTA's chairman and chief executive: "The 2015 season promises to be an exciting season of competition from our top iconic players who will be challenged by our talented next generation of WTA Rising Stars. On the Road to Singapore, every match matters. From the opening serve in Brisbane through the next 42 weeks, the stars of today, tomorrow and the future will compete for a spot in the prestigious WTA Finals. It is going to be an exciting and inspirational 2015 WTA season."

The WTA Finals Singapore will be held at the Singapore Sports Hub, and will continue to be a 10-day sport and entertainment extravaganza. The singles and doubles competition will expand from seven to eight days, with the inclusion of the WTA Legends Classic, WTA Rising Stars Invitational and WTA Future Stars competitions.