Mercedes under pressure to fix F1 handling problems, says Hamilton

The world champion trailed team-mate Nico Rosberg by seven tenths of a second on Friday at Barcelona, and while some of that gap was put down to Hamilton getting traffic on his hot lap, he admitted "the lap wasn't quick enough anyway".

"It doesn't feel great this weekend," said Hamilton, who was third fastest behind Ferrari's Kimi Raikkonen.

"I don't know if it's tyres or the wind, but it's definitely a little bit different to what it was in testing.

"It gives us a lot of homework to do. A lot of pressure on the engineers to analyse what's going on, and for me to do the background work to try to figure out what I can do.

"It's very rare that you get a perfect balance, but we definitely don't have a perfect balance today, there's lots of problems.

"We will work as hard as we can to fix them. There's a lot of improvements to be made."

Hamilton suspects Pirelli's high tyre pressure limits could be playing a part in the poor handling of his car.

"They've put more pressure in these tyres since winter testing, so I'm sure that's not helping," he said.

"It makes the tyres even worse than they were.

"Today wasn't an easy day, but sometimes you have those.

"It was very hard to gauge the set-up and that's what we've got to do tonight to understand it.

"The car doesn't feel spectacular but that doesn't mean it can't be spectacular tomorrow so we will work on it."

HEAT CAUSING LOW-GRIP

Championship leader Rosberg believes the higher temperatures compared to winter testing are behind the lack of grip at Barcelona.

"Now it's 40C [track temperature] and it's a different world to testing," he said.

"The car is different, it's much more difficult to drive, but it's OK today.

"In the winter it's cold and there is so much grip - now it's hot and the car is sliding everywhere.

"It doesn't feel good when you have less grip, but surely it's the same for everybody.

"We're optimistic, we have a great car and we expect to have a good weekend."