"I see this as our ultimate test, I really do," Blackadder said.
"I think they'll test us in different ways, test us in ways other teams haven't.
"I think they'll try to take us through the middle, for example, try to go through the middle with a lot of pick and go, so I think we're going to have to be on our game."
Dan Carter, who celebrated his 100th game for the franchise against the Hurricanes, remains at second-five outside Tom Taylor.
Changes have come in the form of prop and lock rotations, Ben Franks moving to loosehead to accommodate brother Owen, with Wyatt Crockett on the reserves bench. Luke Romano will partner Tom Donnelly in the second row.
Adam Whitelock retains his place on the right wing due to Sean Maitland's ankle injury.
The Waratahs have worse problems, with flanker Chris Alcock, centre Rob Horne and fullback Bernard Foley hit by injury and inside back Berrick Barnes by the flu.
The Chiefs' match against the Hurricanes at Waikato Stadium on Saturday will be the first time the Hamilton-based franchise, the leaders of the competition, have played a New Zealand team since the round three win over the Crusaders.
Halfback Brendon Leonard returns from his hamstring injury in round one to start, with prop Toby Smith back from a long-term calf problem and on the bench. Flanker Tanerau Latimer and wing Tim Nanai-Williams start ahead of Sam Cane and Asaeli Tikoirotuma respectively and hooker Hika Elliot starts ahead of Mo Schwalger.
Having returned from a successful three-match tour of Perth, Bloemfontein and Durban, the Chiefs will be formidable opponents for the Hurricanes.
Finding ways through that Chiefs defence, the second best in the competition, is high on the agenda for coach Mark Hammett.
"Their defence has been outstanding. But we've probably shown against all teams, that against the best defence, we can still open things up and score tries. So that's obviously what we've planned for through our strategy this week," he said.
Hammett will be helped in this regard by the return of wing Cory Jane from an ankle injury. Halfback TJ Perenara (ankle) and wing Julian Savea (illness) also return to the starting line-up.
The Blues have suffered yet another blow with the calf injury to prop Tony Woodcock on the eve of their match against the Reds at Eden Park tomorrow (Fri) night.
Coach Pat Lam has named Piri Weepu to start at halfback where he will mark Wallaby Will Genia.
The Highlanders kick off their South African tour with a match against the Cheetahs in Bloemfontein on Sunday morning (NZ time). Fullback Ben Smith is expected to start after missing last week's win over the Blues because of concussion.
Midfielder Phil Burleigh broke his nose against the Blues but is available to play.
CRUSADERS team to play the Waratahs at the Sydney Football Stadium on Sunday, kick-off 6.10pm (NZ time): Israel Dagg, Adam Whitelock, Robbie Fruean, Dan Carter, Zac Guildford, Tom Taylor, Andy Ellis; Kieran Read, Matt Todd, George Whitelock, Luke Romano, Tom Donnelly, Owen Franks, Corey Flynn, Ben Franks. Reserves: Ben Funnell, Wyatt Crockett, Samuel Whitelock, Richie McCaw, Willi Heinz, Ryan Crotty, Tom Marshall.
