Lions back-rower Jamie Heaslip is tipping NSW coach Michael Cheika will have the Waratahs pumped up for tonight's showdown with the unbeaten tourists.
Heaslip knows the Waratahs coach from his days playing - and winning - under Cheika for Irish club side Leinster.
Cheika's arrival at Leinster in 2005 coincided with Heaslip joining the side, and the Lions star credits the Australian for transforming the club into a European Cup-winning team.
"The club had lost its way a little bit and was a little bit shaky," Heaslip said ahead of tonight's match in Sydney. "They were training all over the place. It was all over the place and Cheiks came in and he just put a really, really good structure and made it like - I always refer it to - an organisation, like in the NFL."
But if Cheika added a professional edge to Leinster off the field, Heaslip said he insisted every player showed mongrel on it.
"He always also kept you under the pump. He demanded the best from players," the Irishman said. "Sometimes the ways he went about that was good for some players, but harder for others to take.
"He was a hard nut, some would say a madman at times.
"He was a fiery character but I had a lot of time for Cheiks.
"I was really blessed because he was a back-row player and I was just lucky because he would kind of see the game as I would see it."
Heaslip has no doubts Cheika would have spent this week firing out expletives at his undermanned Waratahs in a bid to steel them for the challenges of taking on the Lions.
"Knowing Cheiks, he's definitely sticking it to the guys who are there and motivating them, that this is their chance because those guys aren't around," he said.
"I wouldn't put it past him if the pads they're hitting all week were red, or they put red jerseys on the opposition.
"He doesn't like people holding back. He doesn't like people hiding."
Waratahs v Lions
Sydney, 9.40 tonight
Waratahs: Drew Mitchell, Cam Crawford, Rob Horne, Tom Carter, Peter Betham, Bernard Foley, Brendan McKibbin, Dave Dennis (c), Pat McCutcheon, Jed Holloway, Ollie Atkins, Will Skelton, Paddy Ryan, John Ulugia, Jeremy Tilse
Reserves: Luke Holmes, Richard Aho, Sam Talakai, Lopeti Timani, AJ Gilbert, Matt Lucas, Ben Volavola, Tom Kingston
Lions: Leigh Halfpenny, Sean Maitland, Jonathan Davies, Jamie Roberts, Simon Zebo, Jonny Sexton, Mike Phillips, Jamie Heaslip, Sam Warburton (c), Tom Croft, Paul O'Connell, Alun Wyn Jones, Adam Jones, Tom Youngs, Mako Vunipola
Reserves: Richard Hibbard, Alex Corbisiero, Dan Cole, Geoff Parling, Dan Lydiate, Ben Youngs, Owen Farrell, Rob Kearney.