The argument was that it's much easier to justify choosing the 691 HP Tesla over the 585 HP Mercbecause we're not talking about a gas guzzler. The Tesla is an EV, it costs just as much as the Merc and it's the faster accelerating car. This video proves that point. The P85D is just so much faster off the line it's not even fair.
The E63 AMG S does fight back but only after they both reach higher speeds - which for normal everyday traffic, wouldn't even be relevant.
Overall, the cars complete two runs and each run ends up being extremely close. Even if the Model S would have lost, the fact that it's this fast while being environmentally friendly is just incredible. That's what instantaneous maximum torque looks like on the drag strip.