By Simon Cambers
World number three Djokovic made it three wins out of three after demolishing young Belgian Ruben Bemelmans 6-3 6-2, a win that sent Serbia into Saturday's final.
"I honestly didn't expect to be playing this well at the start of the year," Djokovic said. "This week I have been playing my matches and then doing two hours of training.
"At this moment, I feel really good physically and mentally and I believe that I can beat anyone."
Former world number one Hewitt, winner at the U.S. Open in 2001 and Wimbledon in 2002, turns 30 in February but the Australian's efforts at the mixed team event have given him hope that he can make a strong run in Melbourne.
In just his third match back after three months away because of a hand ligament injury, he won his second battle of the week by beating Andrey Golubev of Kazakhstan 6-3 6-3.
Only Djokovic has got the better of him this week and although he has dropped down to 54th in the rankings, Hewitt was encouraged by his outing in Perth.
"I always feel like my ball striking is pretty good," Hewitt said. "I've come off a layoff and to be able to strike the ball like I did with Novak, I was pretty happy with that.
"I think Tony Roche (his coach) and I took a lot of positive signs from that and I've been able to continue it on.
"I'll play three tough matches at (the exhibition event in Kooyong) next week and hopefully that's going to be the perfect preparation for me."
Australia beat Kazakhstan 3-0 but the result had no bearing since Serbia clinched the final spot.
(Editing by Pritha Sarkar)