Wozniacki and Williams are very close off the court, and the American helped Wozniacki get over her widely publicised split with former fiancé Rory Mcllroy in 2014.
They've also enjoyed a strong rivalry on court.
Williams has dominated, winning all but one of their 11 encounters, but most matches have been close.
Their first clash set the tone, a three set battle featuring two tiebreaks in Sydney in 2009.
Four of their last seven matches have gone to three sets but Williams has always prevailed, with Wozniacki's only victory a 6-4 6-4 win in Miami in 2012.
"We always have some hard battles," Wozniacki told the New Zealand Herald.
"Unfortunately most of them Serena won but it has been close. I hope it's my time to get out on top now."
The Dane is part of a star-studded lineup next week, with Serena and Venus Williams, Ana Ivanovic, 2016 champion Sloane Stephens and promising youngsters like Ana Konjuh and Naomi Osaka.
"I think the field is always strong here in Auckland," said Wozniacki. "This year is not any different. It gives a good possibility to be tested from the beginning of the year [by] some of the best players in the game [but] it must be unusual for an international level tournament."
Wozniacki endured a difficult 2016.
She dropped out of the top 50 in June for the first time in eight years, and missed almost three months with an ankle injury.
Wozniacki had surprise first round losses at the Australian Open and Wimbledon and won just two matches between January and June.
There was increasing speculation that she might retire at the end of this year, especially after her father and coach Piotr Wozniacki told a Danish newspaper "I agree she should stop while she is still fresh and do new things."
But Wozniacki rebounded in spectacular fashion.
She reached the semi-finals at the US Open - only stopped by the world No1 Angelique Kerber - and won tournaments in Tokyo and Hong Kong to return to the top 20.
"I never doubted myself," said Wozniaki. "I had a bad injury that took me out of the game for quite some time. I wasn't feeling 100 per cent comfortable coming back and was maybe lacking the last five or 10 per cent. So I think it's normal to drop down a bit after an injury. But I always believe in myself and I know I can win against anyone on the tour."
Wozniacki is back, though she didn't offer a specific time frame when asked how much longer she would like to stay on the tour, after more than a decade as a professional.
"I [will] continue playing as long as I have fun playing tennis," said Wozniacki. "Right now I'm enjoying my time on the court."
Rivals next week - beware.
Caroline Wozniacki at the ASB Classic
Year Result
2009 Quarter finalist
2015 Runner Up
2016 Semi finalist
