Mexican GP Speed Trap: who is the fastest of them all?

We've said it before, but sitting at 2,200 meters above sea level, altitude is everything at Mexico City's Autodromo Hermanos Rodriguez.

Rarefied air means less downforce, which teams compensate for by running more wing, but without sacrificing too much straight-line speed.

And then there are also the demands imposed on engines: the thinner the air, the faster the turbo has to spin to inject oxygen into the unit, a condition that tends to equalize engine performance among the manufacturers.

• Vettel: 'Race will be decided over strategy and tyres'

Overall, Ferrari's power unit appears to be the one that is breathing the most healthily in Mexico as the speed trap readings indicate with all four Ferrari-powered cars leading the field in terms of hseer velocity.

But the fastest aren't always… the fastest.

Poleman Daniel Ricciardo, despite his stunning lap in qualifying, conceded a whopping 15 km/h down the straight to the Scuderia's Sebastian Vettel who only qualified fourth on Saturday!

Who will have the last word on Sunday afternoon?