We talk a lot about how this is a team sport. I hope the teams got a good rest last weekend; they're now in for a long, highly-intense run to the finish.
Over the next 12 weeks, they'll cross the country twice and go as far south as you can go in the continental United States. All while preparing to run races on 12 completely different tracks (including one road course they've never run before and have no idea what to expect from).
Then, there's the whole, "staying alive in the playoffs" thing.
This is when the pressure ramps up. When small mistakes are amplified. The grind of a long season may be wearing on the drivers and crews, but when they show up at the track, all that has to be shoved to the back of their minds.
Physical strength matters; but this time of year, it is the mental strength that wins titles.