Williams was introduced at halftime against England in Newcastle, but struggled to contain shooter Pamela Cookey, who led a third quarter English revival.
England closed to within five goals of the Ferns late in the third spell, before New Zealand kicked on in the final quarter to record a convincing, but hard-fought victory.
"I'm not really happy with that; there's so many things I want to go out there and change - too late now, I guess," said Williams.
She is accustomed to being the first player picked for the Ferns and now finds herself playing a supporting role to Leana de Bruin and Katrina Grant, both of whom have been in exceptional form this season.
"I haven't played for a long time so I'm feeling a bit behind," she said. "I'm still trying to get that confidence back in my knee and figure out what works and what doesn't."
New Zealand coach Waimarama Taumaunu said her star charge needs to keep in mind that it is still very early days in her comeback.
"She is very hard on herself. She needs to recognise that she hasn't had the same amount of practice or court time as the others.
"She's very disappointed about that, but she will get there," Taumaunu said.
