They may also have to do it without their All Blacks captain and flanker Sam Cane, who has until Thursday training to show he has recovered from a knee injury.
Assistant coach David Hill said there had been plenty to discuss from the way they finished against the Drua, and they would be taking the lessons into the Waratahs' game.
They were well aware of the threat the resurgent Waratahs posed, he said.
"[In] Their last four games against New Zealand teams, they've won two, and they probably should have won the other two.
"They've proved they've come a long way since we played them last year, and a long way since we played them this year, so [there's] a good amount of improvement.
"They're a team that starts pretty fast, they've had some good half-time leads. So, we need to match that. They're impressive, well-coached and well-drilled and made some great strides this year so they'll be a threat.
"It's where we want to be, a home quarterfinal. It's one of the goals we set at the start of the year. In terms of that it is one game at a time, because it's knock out footy.
"Not a lot has changed in terms of our week, our prep is very much as we have done previously and a good week so we give ourselves the best chance on Saturday," he said.
The Fijian game had been a welcome experience for the side, he said.
"A 21-point lead with 10 [minutes] to go. A missed tackle on their goal-line, and a 100-metre try, and the next eight to 10 minutes was quite an experience for a lot of our players – the heat and humidity, the crowd and a team that was on a roll," he said.
It resulted in discussion about what they could learn from that match situation.
"It was good, a lot of our guys have never actually been that fatigued, or played in that heat, so that last 10 minutes has been a good discussion around how we can get better and improve that," he said.
It would sharpen the side's act in the last 20 minutes at the weekend, he said.
Hill said Kaleb Trask would not be considered for the weekend as he was going through concussion protocols after being injured in the Drua game.