Ivanovic and Djokovic have enjoyed the rare opportunity to play mixed doubles
Serbia booked their place in the Hopman Cup final after world number three Novak Djokovic beat Belgium's Ruben Bemelmans 6-3 6-2 in Perth.
The top seeds had already defeated Kazakhstan and Australia and needed to win only one rubber in their final Group A match against Belgium.
In the opening rubber, Belgium's Justine Henin continued her comeback with a 6-4 6-3 win over Ana Ivanovic.
Henin and Bemelmans took the mixed doubles 3-6 6-4 10-4 to seal a 2-1 win.
Serbia will take on Italy, the United States or France in Saturday's final, with the Group B standings to be decided on Friday when Great Britain, who are already eliminated, take on the US and Italy face France.
I thought today was probably one of the worst matches I played lately and I really got down on myself
Djokovic, who helped Serbia claim their
first Davis Cup triumph
last month, also reached the Hopman Cup final with Jelena Jankovic
"The last couple of months I've been playing maybe my best tennis and definitely a title in the Davis Cup gave me a lot of confidence,'' said Djokovic.
"'I'm still working hard off the court trying to work physically well and I'm really, really satisfied with the way I've been playing the first couple of matches here. Everything seems to be working. I'm hitting the ball really well, I like the surface and the atmosphere."
Henin is playing in her first tournament after six months out with an
picked up at Wimbledon last June.
The former world number one had already recorded singles victories over Molik and Karatantcheva this week and improved on those performances against Ivanovic despite falling behind to a break of serve early on.
From 2-0 down, Henin hit back to win the first set in 41 minutes before closing out the second set 6-3.
"I'm really happy the way I played," said Henin, who has never been defeated by Ivanovic. "I had a tough start, my energy was pretty low at the beginning of the match and I was bit sleepy at the time.
"She put on a lot of pressure at the beginning and after that I just tried to come back into the court, take every opportunity at the net and be aggressive at the returns, so I can be very happy with the way I played."
Ivanovic said: "I thought today was probably one of the worst matches I played lately and I really got down on myself. I have to be a little bit more aggressive than I was today. It's just getting through more matches and getting more confidence"
Earlier, Australia made sure of victory against Kazakhstan with 2002 Wimbledon champion Lleyton Hewitt beating Andrey Golubev 6-3 6-3 and Alicia Molik overcoming Sesil Karatantcheva 6-3 6-2.
Hewitt said: "I played him at the French Open a couple of years ago and he's a great shot-maker, so it was important for me to go out there and weather the storm against him."