The Kiwi's adopted country will have home-field advantage and will be facing an outfit with just weeks to get ready for battle but he insists the Lions will provide a huge challenge in Brisbane, Melbourne and Sydney.
"We have a great respect for what is coming," Deans told BBC Radio 5 live.
"We have a deep respect for the capabilities of the playing group.
"You only have to look at the performance of England against the All Blacks and then Wales against England.
"We saw in the intensity in that fixture between Wales and England what is coming.
"The Six Nations has been incredibly intensely contested, nobody came through unscathed. The last round determined the outcome, and when you go from the first round to the last round, the whole thing was possibly tipped on its head."
Deans believes the three-match series will be the ultimate test of his coaching credentials of his squad's mental and physical capabilities given the unique nature of what lies ahead.
Facing the same side three weeks running offers an obstacle rarely seen in the modern game, while the element of unknown that always accompanies the Lions simply adds to the magnitude of a truly massive sporting occasion.
"You have back-to-back Test matches and there is intrigue about adaptation. No two Test matches are the same," added Deans.
"There's a lot of intrigue around combinations and a lot of intrigue around the Lions squad itself.
"It probably is the pinnacle (of a coaching career) because of the nature of it."
Deans will have his chosen players in camp for three weeks before the opening rubber at the Suncorp Stadium on June 22 as he seeks the perfect prep to see off the world's most famous touring team.
His decision to keep his star names in house has drawn plenty of criticism, even though the same policy was effectively employed on each of the previous four tours.
Deans insists working with the Wallabies for as long as possible rather than sending out his key men to feature for their franchises is the best way for the Aussies to secure what they, and the Lions, really want this summer: series success.
"The Lions get to play together, but we won't get that opportunity. We will try to replicate match (conditions) as much as possible.
"It is not devaluing the tour matches, quite the opposite. It will ensure we get a preparation of sorts.
"We will make it as effective as possible to make sure we enter into that first Test in as good as possible state."