After leading by two sets and 3-0 in the third, Djokovic dropped his first set of the tournament and had to stave off break points in the fourth before shaking Hewitt off 6-1, 6-3, 4-6, 6-3 in just under three hours.
The top seed said the tough workout was just what he needed.
"It's obviously the first match that I've been tested," Djokovic said.
"It was against the player that I expected to be tested. Lleyton was playing in front of his crowd. Obviously he loves competing against the top guys on the big stage and he proved it again.
"Credit to him as well for being competitive, for not giving up. This is something you can expect from Lleyton, who is very well known for his fighting spirit.
"But look, he had the crowd, he had the big support. It got intense.
"Especially the start of the fourth set, we had some great rallies. It's good to come out from this match as a winner. It was a really big challenge for me to see where I stand."
After piling up 64 wins from his first 66 matches in 2011, the Australian, Wimbledon and US Open champion lost four of his last outings as his phenomenal season took its toll.
But the 24-year-old believes his form, despite his mid-match hiccup against Hewitt, is good.
It will need to be against Ferrer, the winner in Auckland and one of the few players to claim Djokovic's scalp last year, having defeated the fatigued superstar 6-3, 6-1 at the World Tour Finals in London.
AAP
