Engine failures are sabotaging Raikkonen's title hopes

The Finn was demoted 10 grid places at the Italian Grand Prix to 11th after a third engine failure in six races.

"We are just not good enough," said Norbert Haug, the sports boss of McLaren's engine partner Mercedes.

"We've improved our speed dramatically but we are not there on reliability. That is quite obvious, we have to admit that and we deserve to be criticised."

Raikkonen set the fastest time in qualifying at Monza on Saturday by nearly half a second but will start Sunday's race nine places behind title rival Fernando Alonso of Renault, who has a 24-point lead with five races to go.

New rules introduced into F1 this year to keep a lid on rising costs demand that engines last for two entire race weekends.

It always seems to hit us when we are gaining on Renault Kimi Raikkonen

Changing an engine before qualifying results in a 10-place grid penalty and doing so after qualifying means a driver has to start from the back.

Raikkonen's engine suffered an inlet valve failure on the last lap of practice.

Haug said: "We shouldn't be changing the engines three times in a few weeks, so when something like this happens you sit down with your guys, look in their eyes, put your hand on their shoulder and tell them we need to do a better job."

Raikkonen suffered similar penalties at the French and British Grands Prix in July, but still managed to finish second and third at those races.

"We've only lost a maximum of six points because of the previous changes," Haug said.

"It could have been worse, but I'm not proud of it."

"At the end of the day, if these six points are missing from the world championship, I am the first to criticise ourselves.

Raikkonen also suffered retirements while leading comfortably at the San Marino and German Grands Prix this year.

He said: "It's something that shouldn't happen.

"I don't know where it comes from, but it always seems to hit us when we are gaining on Renault.

"Everybody is working as hard as they can and hopefully we can sort out the problems so we don't have them any more, but it doesn't make our life any easier."