Daniel Ricciardo was impressed with Red Bull's Friday performance at the high-speed Autodromo Hermanos Rodriguez but admitted its rivals may have more in hand for the weekend.
Though the quick Mexico circuit, which has already registered the highest speed trap of the season, should expose Renault's power unit weaknesses Ricciardo finished third behind team-mate Daniil Kvyat in FP2. Kvyat and Ricciardo had finished second and fifth in the morning.
The higher altitude of the track also places a higher strain on the power unit but Ricciardo says the slippery nature of the circuit played into Red Bull's hands.
"I think what you lose from the engine and everything you gain from the air's so thin," he said. "The car is a lot more slippery, from what I understand, down the straights. It still feels pretty quick to be honest. We seem competitive today, I don't know how much Mercedes, Ferrari and Williams have tomorrow but seeing that the straights are long I think we're doing okay."
Friday was littered with drivers struggling with the lack of grip at the circuit and Ricciardo expects that to improve as the track gets better over the weekend.
"It's pretty good. I think the track's got a lot more potential, in terms of its so slippery out there. Even in the afternoon when it was dry the high-speed stuff was still very slippery as if it was still damp. I think it's just the new track and a bit of water this morning and probably the oil from the tarmac coming up -- once it grips up I think it will be pretty fun."
FP1 started with a wet track, while light rain hit the afternoon practice session in the closing moments. Rain is forecast to be a threat for the rest of the weekend and Ricciardo thinks that could make qualifying a lottery at a track drivers are already struggling at.
"It's slippery! Sure, we'll all manage [if it rains again] but we're going to be tip-toeing around there and the one who makes the least amount of mistakes will be the quick guy."