The second test gave a hint. The third test confirmed it. Steve Hansen has lost total command of his once imperious All Blacks, with rogue elements starting to tear the place down.
We have witnessed an epic series and an epic failure for Hansen, not because he lost - which he kind of did through a series draw - but for the way the All Blacks played.
Yes, the Lions were good, particularly at working out where the offside line was and finding space in wide zones with ease. But not that good.
The All Blacks have been so bad in some areas that a World Cup re-think is inevitable, which may be no bad thing. Hansen was out-coached by Warren Gatland, no doubt about it, and those of us who doubted the Waikato man's credentials (guilty here) have been left red faced.
Apart from the odd magic moment - provided by rookies Jordie Barrett and Ngani Laumape - the All Blacks were largely awful in the finale at Eden Park in a test which only rose to the occasion because of the occasion.
It was substandard rugby from the two best test teams on the planet, the difference being that the All Blacks have established standards to be compared with, while each Lions team sets their own.
In retrospect, it was a masterstroke by the tourists to play like tourists in the first game at Whangarei, setting the expectations low and establishing fertile ground for an us-against-the-world mentality after they copped a bagging.
While the Lions moved steadily forward, the All Blacks have gone backwards. Not only did they fail to respond tactically to the pressure, but their precision and skills have declined badly.
And dare we say it, maybe the Richie McCaw factor is finally wearing off, that dedication to the basics, the battle, sticking to the plot, the cause.
Two of the most instructive instances of the All Black decline came late in the second test in Wellington, and both involved Aaron Cruden. The replacement back from the sometimes unruly Chiefs franchise gave up a costly and ridiculous penalty for a needless block on a Lions runner, then lobbed the most stupid crossfield hit-and-hope kick you might see from anyone aged above 15.
Cruden will be beyond All Black selection soon. But he could have been dropped there and then, for a lazy shot for glory at complete odds with the All Black ethos, exemplified by the masterful late victory march against Ireland in 2013.
I fear that Hansen has lost his touch, the edge having gone out of his decision making, and perhaps even his voice. The All Blacks tried to win the second and third tests the easy way, with miracle passes and kicks. Kieran Read seemed powerless to alter the tactics.
There have been other bad signs.
Sonny Bill Williams' shoulder hit and red card in Wellington was followed by something almost as bad from veteran Jerome Kaino at Eden park, a vicious swinging arm to Alun Wyn Jones's head which was a borderline red moment itself, although yellow was always the favourite.
The All Blacks really missed the wholehearted team ethos and unifying effect of a Ryan Crotty-type, and as one who sometimes doubted the worth of Conrad Smith, I would now concede that his selfless contributions were probably pivotal to all that success.
It's one of those intangibles, but men like Smith and McCaw can somehow pull men like Cruden and SBW into line. Read, in this series, hasn't.
Why was Beauden Barrett still the goalkicker, when his much more accurate brother was on hand?
The Lions are here to stay, thankfully, a unique part of a sport which defies logic on the field, but does it much more impressively off the field with this army of red shirts from different lands. But they were very beatable, and Hansen's team in its prime would have done so.
Nothing typified the All Blacks' fall more than Beauden Barrett's lack of command and attacking runs - he can no longer be described as the world's best player. Then there was TJ Perenara, flapping his arms at the referee while Rhys Webb picked his pocket in the final moments on Saturday night. Don't start me on Aaron Smith's annoying yelling.
Full marks to Warren Gatland and his Lions, who turned a so-called suicide mission into one which has given much-needed life to world rugby. They have announced a new star in Maro Itoje - Eddie "England" Jones will be licking his lips over the athletic lock's development - and Gatty survived the crushing blow of losing Billy Vunipola before the Lions swamped a London departure lounge.
These Lions and their highly likeable captain Sam Warburton will head home outwardly regretting that they didn't nail an historic victory, and suitably disoriented -publicly - by the strange aftermath that a draw delivers.
Deep down though, they can feel that they won. Kieran Read wore a silver hat to celebrate 100 tests. It was a figurative silver medal.