Mark Webber has admitted that Red Bull Racing team-mate Sebastian Vettel is all but assured of winning a second straight F1 championship following his victory in the Italian Grand Prix.

Vettel stormed to another win - his eighth of the year - to extend his lead to 112 points and could take the title if results go his way next time out in Singapore.

Webber by contrast failed to finish at Monza after an early collision with Felipe Massa damaged his car and resulted in him going off the road.

It marked Webber's first retirement since he crashed out in Korea last season and the Australian admitted that the result in Italy had virtually ended his - and anyone else's - hopes of anyone hauling in Vettel in the standings.

"The Italian Grand Prix was one of those races that remind you how much it sucks not to finish," he wrote in his column for the BBC. "It's been quite a while for me but it's such a frustrating feeling - both for yourself and the for the team after all the effort that has gone in.

"It was doubly disappointing in Monza because the car was better than it has been all year. It felt phenomenal in the first few laps and I just got carried away trying to come back to through the field. I should have been more patient with Felipe Massa.

"Seb won the race again and, although he is not quite champion again yet, we're now all effectively fighting for second place."

Webber's retirement meant he was left with a watching brief for the remainder of the race and he admitted that Michael Schumacher's driving while defending position from Lewis Hamilton had been a step too far.

"It was a unique fight between Michael and Lewis because the McLaren was running up against the rev limiter, so Michael had a speed advantage on the straights," he said. "He could position his car very cutely to try to keep him out.

"There were a few times when Michael returned to the normal line having defended. That's the point of interest because it's not what most drivers understand to be acceptable.

"One incident in particular stood out - Lewis had a clear run out of the second chicane into Lesmo and Michael went across to defend, then came back again. Moving that many times was pushing the boundaries."