Meanwhile, the Sexton/Farrell axis was beginning to stress the short-handed New Zealand defence, as it started to feel the absence of Sonny Bill Williams.
There might have been an argument to replace some or all of those with fresh legs against a short-handed side working overtime. But no, Gatland trusted the evidence of his own eyes.
On Saturday, the Lions performance was not going to be improved purely by "fresh legs", especially against New Zealand, whose fitness levels are second to none.
It was all about players in the groove, beginning to find their "A" games and gradually turning the screw. It was close, but that's how the Lions won.
And that rather contrasted with Steve Hansen - a great coach - who, for once, got it badly wrong with one of his crucial calls.
Aaron Smith was having a monstrously good game for the All Blacks and I was astonished to see him come off in the second half, to be replaced by TJ Perenara. The whole momentum of the game started to change at that point.
On the subject of 80-minute performances, I am in awe at what Maro Itoje brings to the table. He was immense from start to finish and the feeling of invincibility a young tyro like the England lock brings to proceedings should not be underestimated.
It wouldn't occur to him for a second that New Zealand were unbeatable. He doesn't really understand the concept of defeat and long may that last.
No wonder the Lions fans were chanting his name football-style afterwards. There were shades of Ronaldo and Messi in their worship of the man.
The only thing I can find fault with in Itoje's entire performance was that he did leak a few penalties. When you play close to the edge and you are tasked with looking for turnovers, that can happen, but he must try to tighten that a little.
Itoje is an extremely intelligent young man and he will know that.
Overall, it was a compelling game, played in pretty awful conditions. I'm not sure if it came over on TV back home just how heavy the rain was, especially in the first half.
The dismissal of Sonny Bill Williams set the narrative and, for a while, the Lions did not cash in.
I've seen that so many times in my playing and coaching career. It can be just plain difficult playing against 14 that early in a game against a really quality side.
They automatically raised their effort levels and intensity by five percent and the subconscious temptation for the team with 15 is just to take the foot off the pedal a tad.
You have to fight that and it was a battle the Lions eventually won.
Finally, a quick word on that Williams red card. He is not a dirty player.
On the contrary, he is fine ambassador for the game and a chivalrous guy, who is rightly admired throughout the game. But on this occasion, he got it wrong.
That was a tackle from his rugby league days, when it may have been met with more leniency.
For a couple of seconds he lost concentration, his sense of time and place, and paid the penalty. He got it wrong and referee Jerome Garces got it right.
End of story.
