Admitting the side was seriously rattled by the Sharks' in-your-face antagonism last weekend, NSW prop Sekope Kepu said cool heads would be the order of the day at Newlands on Saturday.

That means coach Michael Cheika's famous dressing-room diagram, sneakily captured on a pre-match broadcast before their Reds clash five weeks ago, will be blown up and drawn in extra-fat marker this week.

The Waratahs know what it could do for their season if they pull off an upset victory against the beleaguered Stormers on Saturday.

"We do [poker face] really well against the Australians because some of us are friends and we might have played Wallabies level with them, and you don't want to give them anything," Kepu said.

"Personally you get the message that the South Africans look at the Aussies and don't respect us for being physical, and a few of us overreacted.

"You have to be physical in a controlled way, and they niggled us and got under our skin. That's no excuse, we could have kept it in check."

While the Waratahs have hit an unusually rough patch with their scrum this season, the Stormers have struggled at lineout.

Coach Allister Coetzee has used six different second-row pairings and three different hookers in the side's six matches this season.

It is an area where NSW will look to target their hosts, but will require a massive improvement on last week's performance.

"We have enough leaders and experience to take charge there, but there were things going through our minds, we were behind [on the scoreboard] and a bit flustered," Kepu said.

"That was when we needed to find our composure, let it go and focus on the next lineout. If we had gone up in that lineout and caused a fumble, it could have changed the dynamic of the game.

"It's simple things like that. You can talk about it in hindsight, about what could have happened, but it was a big learning curve."

The Stormers will be missing captain Jean de Villiers with a meniscal cyst, as well as winger Gio Aplon (elbow) and second-rower Jurie van Vuuren (shoulder).

Kepu said the key to the Waratahs' 21-15 win in Sydney last week was shutting down No.8 and replacement captain Duane Vermeulen and second row Eben Etzebeth, presumably while wearing their best poker face.

But despite the Stormers' four-straight tour losses on the road this year, the Waratahs have their own demons to purge. NSW have not won at Newlands since 2006. Before that they boasted a paltry two wins in Cape Town.

"They're another big pack and they're awesome at home, so we have to soak up the environment there and use it to our advantage," Kepu said.

"It's a cliche but you want to put points on them early and quieten the crowd a bit, and that will work in our favour."

After a quiet night in attack last week, there would be easier teams against which to light up the scoreboard.

The Waratahs mustered an impressive defence against the Sharks in Durban but dropped the ball – literally and repeatedly – in attack.

A better balanced performance and an inscrutable poker face will be needed this week.

"There is never the perfect game. You do things perfect this week and forget about the things you did the week before," Kepu said.

"But if you want to be the best team, you have to knock everything on the head every week and be consistent. That's what we're striving for. We have to get these next few weeks right, perform well and go back home with two victories on the road."