They also found their late penalty for yet another act of ill-discipline by the legs when Kyle Sinckler was taken out in the air. Maybe it was a bit unlucky on the All Blacks, but they will know that on balance, this was a game they were destined to lose once Williams had been sent off.
There can't be any complaint with the colour of the card. The head is sacrosanct and accidental, deliberate, clumsy, badly timed, unlucky...doesn't matter the nature of the contact.
The image was undeniable: Williams' shoulder connected with Anthony Watson's head and there weren't a lot of arms to at least soften the impression it looked like something straight out of the NRL.
The All Blacks prepare for most, all, possibilities but a red card is always the one they hope they never have to confront in a game. Scrambling through a yellow card for 10 minutes is hard enough, but to face 55 minutes a man down was a monumental task.
That's a glacial time period by rugby standards. There's so much extra ground to cover - not just one defence but attack, too, where the support runners have to find a way to be on hand to create a numerical advantage.
As soon as Williams was off, the All Blacks coaches made the decision to take off Jerome Kaino and bring on Ngani Luamape.
They were willing to go seven versus eight in the pack, but keep the numbers even out wide. It wasn't really the circumstances in which they would want to send Laumape into battle on debut, but it wasn't as if they had any choice.
They were in desperate measure territory. Whatever plans they had pre game, were suddenly all off and it would be back to basics. Hit up the middle hard with anyone and everyone. Smash it up and keep going - it was all about not giving the Lions any space to hit back on the counter. And to deny them the ball - it's hard to score points without it and the longer the All Blacks kept it, the more pressure it exerted on the Lions.
They knew that with a man advantage they should have been dominating. They needed the ball, needed to be scoring points and somewhere in their heads the thought would be building up that that they might not be able to beat a team with 14 men.
That pressure in their heads built as the All Blacks kept the scoreboard ticking over and got nearer to the 80 minutes still ahead.
But their moment came when Conor Murray twisted and turned to find a way over and the Owen Farrell could convert a relatively easy penalty with four minutes left.
British & Irish Lions 24 (T. Faletau, C. Murray tries; O. Farrell 3 pens, con)
New Zealand 21 (B. Barrett 7 pens)