An hour after the Canadian Grand Prix had finished, Christian Horner walked quietly into the Red Bull office carrying a graph. The 24 coloured lines on the sheet told the story of the race across 70 laps.

The graph showed Sebastian Vettel had led from pole for 15 laps, dropped to third after a pit stop, moved up to second behind Fernando Alonso’s Ferrari when Lewis Hamilton relinquished the lead and made a second stop on lap 50. Vettel, at that point, looked certain to give Red Bull a finish on the podium.

But then Horner’s finger ran along Vettel’s line until he came to lap 63, when a drop on the graph painfully represented where their race gone downhill in every sense thanks to a late pit stop with seven laps to go.

Vettel would eventually finish fourth, beaten by the two-stopping Hamilton who had made full use of his fresh tyres to storm from third and into the lead. That much Horner could just about understand.

But then his finger hovered over the lines of Romain Grosjean and Sergio Perez as the Lotus and the Sauber rose to second and third places. Both had stopped just once. And Perez had come from 15th on the grid!

Horner shook his head. “Sums up this season,” he said. “You just don’t know what’s going to happen. It’s incredibly challenging. We had been looking good all the way through. But then Seb’s tyre performance hit a wall. We had to stop and then salvage what we could. You just can’t tell. I mean, look at Alonso. He was leading with seven laps to go. But he finished fifth.”

Alonso, having stopped just once, had run into serious tyre trouble and was powerless to stop Hamilton, Grosjean, Perez and, finally, Vettel, pass the Ferrari as if it was standing still.

Next door, Martin Whitmarsh didn’t need a graph to demonstrate what had happened. The drama of the afternoon was seared into his mind as McLaren stuck to their two-stop plan even though they were uncertain what Ferrari and Red Bull were about to do.

Hamilton had been the first to stop, made good use of his tyres and jumped from third to first. He was still leading when McLaren took a deep breath, followed their plan and brought Hamilton in. Immediately, Hamilton was lighting the timing screens with a succession of fastest laps. Okay, he would catch Alonso and Vettel. But would he be able to overtake? Had McLaren made another tactical error?

“I was very surprised I was able to look after my tyres early on and be able to push when needed,” said Hamilton. “Then to catch Seb and see his tyres go was one thing. But I knew Fernando was the one to beat as he had great pace on long runs during practice. I really don’t think I could have done one stop as I would have fallen back too much. As things turned out, that final stint was one of best I’ve ever had. And the great thing is you can overtake here and, to be honest, you don’t really need DRS to do it, although that does help. When I was catching them, I could see what was possible. I had lot left in me and the car. I had so much traction and they were close to the limit.”

The vagaries of 2012 were demonstrated by Hamilton’s team-mate as Jenson Button, so dominant in Australia, went nowhere all weekend and finished a dispirited 16th. Modifications to the rear suspension on his McLaren hadn’t worked and he struggled for grip and dealt with locking brakes.

“Jenson hasn’t done anything wrong or driven badly,” said Whitmarsh. “The window you need to make the car and tyres work is so incredibly narrow. Get it wrong, and you’re nowhere. I’d like to be able to say that this win means we’re on course for the championship. But we could get to Valencia in two weeks and struggle. That’s the way it is in 2012.”

Hamilton became the seventh different winner in seven races – and he did it at the track where, seven years ago, he scored his first F1 victory. This one tasted just as sweet as it ensured his position at the top of the drivers’ championship.

“Amazing, isn’t it?” said Hamilton. “A win is worth 25 points and yet I’m only leading by two points. It really sums up this season. It’s all about consistency.”

Horner agreed but, looking at the story of his race, achieving consistency in 2012 seems to be as difficult as winning more than one Grand Prix. Or, come to that, finishing on the podium.