The finishing stroke was the difference. As Peaty came under the flags with five metres to go he was fractionally ahead of Nic Fink and Italian Nicolo Martinenghi. However he was on a half stroke.

What it means to be on a half stroke is that with only five metres to go you need to adjust your length of stroke so that on your last stroke you can finish on a full stretch.

With the benefit of afterthought, and the benefit of sitting on a couch while analysing, I can be critical. I can’t tell you what it’s like to be in an Olympic final with one stroke to go and two other swimmers have one stroke to go. So let me first say ‘congratulations’ to all those swimmers! But what happened?

Peaty made the error of finishing imperfectly. He should have stretched his penultimate stroke more and also his stroke before that. He had passed the swimmer beside him in lane five (Qin Haiyang lane 5) and may have thought he was a clear winner. On his very last stroke, as he drove for his touch, he had slightly too far to go. He reached out his hands, kicked his last kick, and as he reached for the wall his top speed was attained, then, just after his top speed was attained, he started to naturally slow down, almost imperceptibly, then touched. In a perfect touch, as you reach for the wall, and you do your last kick, you’d touch just as you reach your top speed. He missed that and had to glide.

Martinenghi timed his finish better. As he swam under the flags (5m mark and red lane lines), he was on a full stroke. But also on a full stroke was American swimmer Nic Fink. Martinenghi stretched out just slightly more than Fink on his second last stroke. Both swimmers where behind Peaty as they all drove for the wall.

As the three were reaching to touch, the only difference is the timing of their last kick. Peaty kicked first and over-stretched. He was too far from the wall by inches. To swim fast in breaststroke you must start your next pull after you kick but on the touch this does not happen; once you’ve done your last kick you can only glide. 99 times out of 100, that good touch would win. But it took a perfect touch. Fink kicked after Peaty and as he touched he had caught up to Peaty. Martinenghi had stretched out more in the strokes before and kicked last. Martinenghi’s timing was perfect, so as he reached for the touch, as he was at top speed, during his last kick and won by a margin of hundredths,. He hit the touchpads at top speed, went past both Peaty and Fink, only as he touched.

With five metres to go each swimmer has to keep their head in their lane. Each swimmer must decide how to make the perfect touch. Not an easy task in the heat of battle. On this day, the Italian swimmer, Martinenghi, changing his life forever, made the perfect decision, he did his touch in a way that he’d perfected with years of practice, and won an Olympic gold. A gold that could have been won by any of the three with one stroke to go.