Brazil are South American heavyweights with eight Copa America Femenina titles but that has not yet translated to success in the World Cup where their best finish was runners-up in 2007.
They began the year with losses to Japan, Canada and the United States but arrive in Australia with victories over Germany and Chile.
"We're really happy with the last two results because we gained a lot of confidence. We can just look at each other and we know it's a little different from a year ago," Sundhage told reporters.
"The most important thing is we don't take anything for granted and please enjoy the game...
If we put together a beautiful attack and very solid defending, then we have a chance to play many games, (go) all the way to the final actually.
"We're in a special team and I think the keyword is 'juntas' (together). There's a lot of energy in the room and it's contagious. We have some young and old players, like Marta - that mix will help us win the next game."
Marta could become the first player - man or woman - to score in six World Cups after Canada's Christine Sinclair lost out on the honour when her penalty against Nigeria was saved.
Sundhage said Marta is '100%' after working with the high-performance coach but would not confirm if the 37-year-old veteran, who is playing in her last World Cup, would start.
"We're not picking the two best forwards. We will pick forwards who connect with each other," she added.
"We've not decided yet (who will start). We have one more training session."
Panama are making their World Cup debut and when Sundhage was asked if she had watched them play, she said: "We know everything about Panama! I've been watching, the assistant coach has been watching so many games.
"We tried to figure out from last seven to eight games what kind of starting lineup they will come up with and how they're going to play... We are prepared for sure, regardless of the formation they play."