McLaren duo Lewis Hamilton and Jenson Button have called for big improvements from their team after failing to match the pace of rival teams during Sunday's German Grand Prix.

Hamilton and Button finished fourth and fifth respectively, more than 25 seconds behind race-winner Fernando Alonso of Ferrari.

Hamilton, 25, said he did everything he could but was let down by the performance of his car.

"I did everything I could at the start because I knew that that was the place where I could really make up some ground," said Hamilton.

"Unfortunately, the guys in front were phenomenally quick, but I still managed to make up a couple of places."

"It was a very tough race - the car didn't feel fantastic and the Ferraris and Red Bulls were very fast. We hoped the gap would be closer in the race than it was in qualifying, and it was. But, even so, we've got to make up some pace on our main rivals."

The 2008 world champion added that improvements must be made if McLaren is to maintain its lead in the championships.