Kobayashi and Maldonado stopped on laps 25 and 30, still looking too far off productively making it on one stop after all; but Raikkonen stretched his first stint to lap 40 and Perez a lap further still. Whether that would work out for them, only time would tell - just as it would for the race leaders.
Although he was out in front, Lewis Hamilton has getting a nasty feeling about how this was looking. He'd backed out of the fastest laps for a time and Alonso and Vettel had duly closed up to him, and now he was getting a bad case of paranoia: what if neither of them pitted, as he was planning to do? How badly would this leave him in terms of track position?
McLaren reassured him: of course Alonso and Vettel would pit again. It was the only sensible strategy. Hamilton was still on edge and started to pull out some fast laps again, but his tyres were suffering and he soon realised that there was no way he could make it to the end of the race without a second stop come what may, so in he came on lap 50. Once again there was a glitch in the pit stop, an issue getting the right rear wheel tightened up that cost potentially crucial time.
Now McLaren waited for Ferrari and Red Bull to respond to their lead and bring in their own drivers: and it didn't happen. They delayed and delayed until the moment was past, the de facto
decision made for them: Hamilton's worst fears were realised, as it became clear that Alonso and Vettel were going to tough it out and try a single stop strategy. Now there was nothing for it except for Hamilton to go all banzai on them and move Heaven and earth to chase them down and try passing them on the track instead - do it the old fashioned way after all.
McLaren had got it wrong in second-guessing their opponents' strategies; but it soon became clear that they had also been spot on about a one-stop strategy being suicidal late in the race, at least as far as Ferrari and Red Bull were concerned. Hamilton was flying, but Alonso and Vettel were grinding slower and slower with every passing minute. A seemingly insurmountable lead soon became a possible one, and then a likely one, and then child's play for Hamilton to dispense with. When he caught up to the back of Vettel in the DRS activation zone on lap 61, the Red Bull practically shrugged and waved Hamilton past.
Alonso was less obliging when caught and tried to stay ahead for a lap or two, but the writing was on the wall and finally even the hardest racer on the track - with no love lost in the past with Hamilton - conceded the inevitable and Hamilton was finally back in the lead entirely on his own merits on lap 65. Job well and truly done, and a victory well deserved for the Englishman, making him the seventh different driver to win a Grand Prix in seven races so far in 2012.
Now it was a matter of who would be joining him on the podium. Having committed to the single-stop strategy, Alonso and Vettel seemed doomed to slog on to the end. But Vettel didn't like that plan and dived into the pits for a late stop, even though it meant rejoining the race down in fifth place behind Sergio Perez, one of the very few to make the single stop strategy work in Montreal - but he has past form on pulling off outstanding results by somehow having better tyre management skills than the average racer, so perhaps that could be expected.
Far more unlikely was Romain Grosjean in the Lotus: he'd pitted only a couple of laps later than Alonso and hadn't been in again since, and yet somehow his tyres were in much better shape than those of the Spaniard. He tore chunks out of the Ferrari's lead and then coasted past on the run through the DRS activation zone on lap 67 to claim second place. It was a strange, logic defying moment: Alonso's collapse in form proving McLaren's assertion that the single-stop strategy couldn't possibly work; and Grosjean's flying pace proving the exact opposite at the exact same time.
Alonso's misery was completed on the final lap when Sergio Perez demoted him off the podium on the final lap; and then just to rub salt in the wound, Sebastian Vettel arrived at the scene - sparking off the Wall of Champions in his rush - to put that late new set of tyres to good use to claim fourth place from the Ferrari as well.
Nico Rosberg recovered from early traction issues to come home in sixth place ahead of Mark Webber after fairly quiet but nonetheless productive races. Kimi Raikkonen's single-stop strategy didn't pay off nearly as well as that of his podium-bound team mate but he still finished in the points in eighth ahead of Kamui Kobayashi who had been on a similar strategy to the Finn. Felipe Massa held off di Resta for the final point in the top ten.