Alonso, Vandoorne set to start from back of grid

Although the size of the penalties has yet to be confirmed, both men implied that they are changing all power unit components, which will mean 35 places.

McLaren sees Brazil and Abu Dhabi as more favourable venues than Mexico, and is trying to complete those weekend without further penalties.

"Unfortunately I think we'll have to change the engine again, so we will start at the back," said Alonso.

"Probably this circuit is not the perfect one for our package anyways, so we expect not to be super competitive here, so maybe it's the best place to take the penalty, and hopefully invest in Brazil and Abu Dhabi with this new engine.

"Once you start last it's better to start last with all the components fresh, so I guess we'll take a lot of them."

Vandoorne had already started the previous race in Austin from the back of the grid. 

"We're taking some engine penalties this weekend, because we know it's a tricky weekend for us," said Vandoorne. "I think for me it will be the full package, so 35 places.

"Hopefully it should be the last, we knew that this was going to be a difficult weekend for us in terms of performance, and we were always planning to take an engine penalty here to kind of protect the last two weekends, where hopefully we should have more opportunities.

"To be honest, I know how to deal with these situations now! Obviously it changes the approach to the weekend, because you're not necessarily focussing in extracting everything out of qualifying, it will be much more biased to preparing for the race."