The Lions took a 1-0 lead in the series after edging out the Wallabies 23-21 in a tense opening encounter in Brisbane on Saturday.
However, Heaslip insists that the tourists should treat the remainder of the series as a two-legged contest in order to secure the victory.
"In a way this is like knock-out football. They will scratch that game and we have to scratch that game as well and start all over again," Heaslip told reporters."It is like the back-to-back games in the Heineken Cup come Christmas time. They are always tough and you know a little bit more about each other and the second game is always a whole lot tighter than the first one, although I don't know how much tighter it can get.
"It is going to make for an interesting second game this week. We'll see what we did well, what we didn't do well., what we've got to work on and what we want more of. I think our patterns worked very well in Brisbane when we got into the way we wanted to play the game.
"We caused a lot of problems. We made little line breaks and half line breaks, but we need to hold onto the ball a bit more and play in the right spots this weekend. We made a couple of silly errors and lost some momentum and gave it to them. Those are the things we have to work on and I'm sure they have a lot of stuff to work on as well - we know they are going to be coming at us hard next week."
The second Test takes place this Saturday.