The easy decision for Jerome Garces would have been to give Sonny Bill Williams a yellow card, but if the referee hadn't brandished the red, the integrity of the game would have been seriously damaged.
In such a high-profile game, involving one of the most recognisable faces in world rugby, if he doesn't get a red card for a hit like that the game from the top down would face serious repercussions.
Put it this way: if Sonny Bill gets a yellow card, young kids watching it would think that it's okay to tackle like that when they go out and play on a Sunday morning. It's the same for referees in charge of schools and club games; what message would it have sent out to them?
It was a blatantly dangerous action that could easily have been avoided. There seemed to be intent there to hurt Anthony Watson, who was very lucky to avoid a really nasty injury.
We all know that Sonny Bill loves to put in big hits - it has pretty much become his badge of honour - but there is no place in the game for that. It was recklessly wild from a guy who is 6ft 4in and 110kg of incredible power.
We often criticise referees, but Garces deserves huge credit for making such a big call in a hugely pressurised environment. And, ultimately, it was the correct one. The TMO George Ayoub didn't seem to agree, nor did Jaco Peyper, who was one of the touch judges, as both encouraged Garces to check the incident again.
Did they feel it only warranted a yellow? Interestingly, Ayoub was the TMO when Ireland played in Paris last year, when some of the hits that the French players put in were, like Williams', over the top.
When a situation like that arises, the man in the middle has to have the final say and take control. That's exactly what Garces did. Plenty of other referees would have crumbled under the pressure.
A four-week ban is probably about right for Sonny Bill. No one wants to see players being suspended, but when it's warranted there is no choice.
When World Rugby introduced the new tackle laws in January, for the first couple of weeks they were policed very heavily. Since then, though, there have been a lot of neck rolls and high shots that have gone unpunished.
This will send out a really important reminder that you have to protect players on the pitch. Again, that's what Garces did.
I would genuinely say the exact same thing if a Lions player committed the same offence. I certainly do not wish any ill feeling towards Sonny Bill, but this is bigger than just this game.
In Sean O'Brien's case, I never thought he should have been cited. Thankfully common sense prevailed in that instance. O'Brien was immense again on Saturday and it's great to see him back to his best.
For me, a yellow card was the correct call for Mako Vunipola, even though the outcome could have been worse for him. It was a really silly decision on his part and his Test place might well be under threat from Jack McGrath.
The All Blacks play the game on the edge, but they are not a dirty team. They do play extremely hard and with incredible intensity, but that's what makes them the best team in the world.
It might have been the first red card they had received in 50 years, but if you go back to the Aviva last November, Malakai Fekitoa should have been sent off for his tackle on Simon Zebo, so you could easily say they should have had two in recent months.
It took a lot of work from the Lions players to get the job done on Saturday, but there is no doubt that they could have made it easier for themselves.
Their discipline was poor and they just didn't hold on to the ball for long enough periods. The All Blacks had 61pc possession, conceded eight penalties to the Lions' 13 and made double the amount of tackles.
When the Lions started to play rugby in the last 15 minutes they were outstanding. Their execution was hugely impressive as they started to find the gaps.
They got lifelines in the game and we shouldn't forget that. New Zealand opened the door on several occasions, but up until the 60th minute the Lions didn't look like breaking through.
They lost control of the game from the 20th to the 60th minute and that has to be a concern when you are playing with an extra man.
Warren Gatland was under pressure coming in to the game, but he got the big calls right. Johnny Sexton and Owen Farrell worked well together and I would expect both to start again in Eden Park on Saturday.
Sexton is a big-game player and, once again, he didn't shirk any of his responsibilities. Farrell was the same. There was a lot of traffic down their channel, but they coped well.
We knew all week that the weather was going to be monsoon-like, so the easy option for Gatland would have been to play Ben Te'o, who was pretty effective in the first Test.
It was a brave decision to go with Sexton and Farrell and it paid off. The execution for Faletau's try was superb and any team that scores two tries while shutting the All Blacks out deserves massive credit.
The Lions will enjoy a couple of down days this week, but Gatland will be mindful that several aspects of their play have to improve if they are to clinch the series. The All Blacks will be seething, but the momentum has shifted in the Lions' favour. They must take full of advantage of that.