While the opening test at Jerez suggested that the McLaren MP4-28 should be one of the pace setters this year, Jenson Button feels there's still a long way to go as he and the team seek to understand the car.

With today's running compromised by the weather, the Woking team already faced a massive programme next week however, Button feels the team must work flat-out in order to get to grips with the car.

"It's been a very difficult few test days for me in terms of mileage," he told Sky Sports F1. "It's been very tricky to understand where the car is. At times the car feels good, at other times it doesn't. And a lot of that is basically understanding the car that we have and making sure it's working as we expect it to be working.

"I really am looking forward to a good test next week because I don't feel we've been able to do enough to really understand the car and where we are with the car," he added.

Like his rivals, one area of concern is the high rate of degradation with the new rubber, the softs only good for a couple of laps.

"You have to throw a lot of new tyres at it and we don't have that many," he admitted. "So it's difficult to do set-up work and comparisons. I think we have a good base and if we can extract the best out of the car I think it is a good car. It's just that at the moment I don't think we're doing that."