Lewis Hamilton plays down Ferrari threat to Mercedes in Mexico

Vettel edged Hamilton by 0.004s in FP2, but the Mercedes driver played down the significance of that performance, as he believes he could have gone quicker on his super-soft tyre run.

When asked after practice if Ferrari is a threat this weekend, Hamilton said: "Tomorrow we will find out. I don't think so.

"They look like they are quite quick. They are not as quick as us at the moment, but maybe tomorrow it will be different.

"I had more time in the lap that I did, my best lap was about lap five or something, so the tyres were old.

"It will be interesting tomorrow, I hope they are in the battle with us.

"Practice was strong for us, I got a lot of laps, a good understanding of long runs and low-fuel runs.

"Now it's about digesting that and [working out] how to make another small step for tomorrow."

Vettel also expects Hamilton to show more pace on Saturday, and he believes it is too early in the weekend for Ferrari to get excited about its performance.

"We are ahead, but Lewis's lap didn't look particularly good and I think he has more in his pocket," Vettel said.

"We need to be realistic, not judging today on the result but judging the feeling of overall pace.

"But we didn't have any problems, we were ahead of schedule, which is a very good sign, so overall it was a good day.

"The pace was very good here last year, so maybe there is something about Mexico which suits Ferrari.

"But it's difficult to say. If we are in the same position tomorrow we can get excited."

Rosberg played down the 0.4s gap to championship rival Hamilton, highlighting the different tyre strategies used at Mercedes during Friday's running.

"I was focused on running the harder tyres, Lewis was focusing more on the softer tyres," said Rosberg.

"Everything is going in the right way, but Ferrari was a bit of a surprise so we need to do some homework tonight.

"Today was very cold and that made the cars very, very nervous - quite a handful out there."