"We are 'brown bread' if we don't win at the weekend. It is do or die for us and there is no buffer. We wanted to win every game, and that's not realistic now, but we'll be happy with a series win," said Hooper.
"We have to take it game by game now, whereas earlier we were thinking about winning the series from the start. There is huge pressure on us and we need to win this weekend.
"Coming down to a series decider in Sydney would be really exciting, so we've got to put everything into this weekend. It is huge for us.
"We put ourselves into a position to win last weekend and we have to do that again. It starts with defence, good work at the breakdown and then I'm sure the attackers will take care of the rest.
"We've just got to put ourselves in a good position like we did last weekend and, if we tighten up a few things, I'm sure we'll get there.
"Team spirit has been growing for some time and we've had three weeks to build on that. There are good combinations from each club and the team is at a point where they know each other well and we will do what we need to get the win and help each other out."
One area Hooper knows the Wallabies must improve is in their goal kicking department. The difference between the two sides in Brisbane was the near faultless display with the boot of Leigh Halfpenny and the 14 points the home side left out on the pitch through five missed kicks.
But as well as improving in that area - Leali'ifano will take over the kicking duties if he is declared fit to play - Hooper is well aware that he and his back row colleagues must not infringe anywhere within 50 metres of their posts.
"We left a lot of points out on the pitch and they are sometimes points you take for granted when they are being kicked. We can't let that happen again," he added.
"When Leigh Halfpenny is lining up a kick at goal you just line up your run back to the to the half-way line because you know he is going to kick it. It does make our job as a No7 more difficult because you know you can't afford to give away any penalties in your half. It's tough, but it helps to clean up our play a lot.
"I enjoyed by battle against Sam last weekend. He is a fit player and gets through a lot of work and you always want to play against these guys.
"He is one of the players I've wanted to play against for some time, ever since I saw him do that dump tackle at the World Cup. It was good and, hopefully, we are in for another battle this weekend."
Hooper is hoping for another wonder show from his Waratahs team mate Israel Folau, who crowned his Test debut with a brace of tries, and believes rugby union could yet be the best code the former rugby league and AFL player has starred in.
"There were a lot of positives for us to take out of that game last weekend. We didn't have much ball in the first half , we scored two tries and Israel Folau was outstanding," said Hooper.
"He is amazing, isn't he? That was a great start for him and, as with every player he'll just want to chase consistency now. I am sure that's what he wants to do because this could be his best code yet.
"I've had the luxury of playing with him all year at the Waratahs and so it was just another week for me watching him do what he did. I hope he can reproduce those performances at this level and enjoy it because it's an experience he couldn't have got in league or AFL.
"He is a legend - he's quiet and just does the business. He is really down to earth and a good guy who just goes about his business. He has played three different codes and he has come into this one and done pretty well."
But while Hooper is looking for more of the same from the Wallaby wing, he feels for the Lions in their loss of lock Paul O'Connell.
"He is an intimidating figure, especially when you see hi standing across the way from you at a line-out. He must be a big loss for them in their camp," added Hooper.
"He finished the game with a broken arm so you can see how much he wants to be there. There will be someone just as good to step in. Maybe he won't be such an emotional springboard, but skill wise he'll be just the same."