"He's a wonderful reader of the game. He implements the strategy well and that pace that he has can unlock defences."
Barrett's performance in the 40-12 victory would have pleased the 27-year-old, who in recent weeks faced calls to be replaced in the All Blacks by the in-form Richie Mo'unga.
"It was a wonderful virtuoso performance but Beauden will just put that behind him and focus on the next task," he said.
"We [the All Blacks] just concentrate on our next task. What's the next job we've got to do?"
That would be seeing off a confident Argentina in Nelson in 11 days, after the Pumas humiliated the Springboks 32-19 in Mendoza last weekend.
Fans could expect to see a couple of new faces in the squad for that test, Fox admitted.
"We have a massive amount of respect for Argentina. We will respect them by making sure we're picking the strongest team we possibly can but we've got a big squad and you can't carry this group of guys and not give people opportunities," he said.
"That's not good for the environment for a start and you never know when you're going to need them.
"Some will get an opportunity, there's no doubt about that. Some of that will come from a bench point of view. There'll be a few changes to the starting line-up but nothing that's major," Fox said.