McLaren: We have work to do

McLaren boss Martin Whitmarsh has admitted that the team need to work out how to get more tyre performance on their low-fuel runs after struggling for single-lap pace around the Circuit of the Americas on Friday.

On the face of it Red Bull enjoyed one of their most dominant starts to a weekend of the whole season on the first ever day of practice at Austin's new circuit as lead runner Sebastian Vettel set the pace in both sessions by over seven tenths of a second.

McLaren ended up fourth and fifth on the afternoon timesheet, but their fastest time was a full second slower than Red Bull's in comparative runs on the medium tyres.

And although the situation over the longer runs looked far closer at the end of the session Whitmarsh conceded that the team had yet to get the tyres sufficiently up to temperature for qualifying simulations.

"Today the circuit seemed very shiny, I think it's exacerbated by reasonably conservative tyre choice here," he said in the Friday press conference.

"So I think we're going to have to work hard - certainly we know we've got to work hard on low fuel.

"We found it a little bit easier on high fuel, which suggests we weren't working the tyres well enough on low fuel." The opening day at CoTA witnessed an unusual number of incidences where drivers ran off the road during practice, with both the low-grip surface and general nature of the circuit consistently catching drivers out.

Whitmarsh acknowledged that the layout was proving an intriguing challenge for drivers and teams alike.

"Some of the corners have got some unusual challenge which makes it an interesting challenge," he added.

"It's slippery, there's some interesting cambers on the circuit and some interesting compromises you've got to find between the vast variety of corners that we have."