McLaren F1 team expects to slip back as Mexican GP progresses

Jenson Button and Fernando Alonso were eighth and ninth at the end of Friday practice at Mexico City, a result the Briton admitted was "a little bit unexpected".

The performance came despite concerns that Honda's lack of power would hamper McLaren on the track's long main straight, where F1 cars are reaching their highest straightline speeds of the season.

Asked if he felt the Friday result was representative of McLaren's true pace, Boullier told Autosport: "I think it is, but it's a new track, new asphalt, oily asphalt.

"When you have an oily asphalt and no grip cars with more downforce are favoured compared to ones with less.

"This is why you have a change of the order and you see us in front of Lotus and Force India. We have more downforce than them.

"The more the track will get grippy the more these cars with the powerful [Mercedes] engine will recover some pace.

"Plus the fact they have some [extra] power during qualifying. We haven't seen that yet."

Alonso has already said McLaren is unlikely to push for single-lap pace on Saturday as both cars face grid penalties for engine changes.

Boullier believes a Q3 place is a long shot in any case.

"It's nice to see some signs of improvement but I don't expect to be eighth and ninth [in qualifying]," he said.

"Eleven and 12 maybe, but not more."