What really matters is that they are both here, something that almost never happens for a tournament of this size. The WTA tour has different tiers, from Premier Mandatory (Indian Wells, Miami, Beijing, Madrid) to Premier 5 (Dubai, Rome, Cincinnati, Toronto, Wuhan) to Premier (12 tournaments including Brisbane, St Petersburg and Tokyo). The ASB Classic is classified as an International level event, at the lowest tier.
The last time the Williams sisters were seen together at a tournament of this size Jenny Shipley was Prime Minster, Winston Peters was her deputy and Taine Randall was the All Black captain. It was March 1998, and the Williams sisters both entered the IGA Classic in Oklahoma.
Venus won the singles title - her first at WTA level - and the pair also picked up the doubles trophy. Since that time they haven't featured together at this level.
It's mainly because Serena tends to prioritise the big events; last year she only played eight tournaments (the four Grand Slams, Rome, Miami, Indian Wells and the Olympics) and in 2015 just 11.
But she's here, and Venus was taking most of the credit today.
"She got here and I have been making promises for years," said Venus. "I am literally taking credit. And it's nice to have family here. At the end of the year we have to leave our family so that is a sad moment but then you come and family is still here and it's a warm and happy feeling [though] it's quite competitive too.
The siblings have met in countless big games over the years - including eight grand slam finals - but remain very close. Indeed, Venus admitted that having Serena on the tour helps to keep her going.
"Yes, for sure, I definitely think so," said Venus." I don't think about one or the other not being here but if that happens then we will cross that road and we will deal with it."
Venus was tipped to retire after the Rio Olympics, but she is lining up again, for her 23rd year on the WTA tour.
"Here we are and here I am," said Venus. " I have no explanation about what is going to happen to me in the future but I am still pretty good at tennis actually so while I can I will be here. The goal at the moment is to continue to win matches."
She also expects Serena to be back on the victory trail this year, after a below par year in 2016.
"If she wants to win, she probably will," said Venus. "It's not that easy of course, she's been the best for a long time, it takes dedication and amazing mental strength. She has played a lot of matches in her life and that experience counts for a lot."
Serena faces Frenchwoman Pauline Parmentier, in the first match of the night session on Monday.
