Sebastian Vettel has admitted that his retirement from the Italian Grand Prix has not only dented his championship defence, but also casts doubt over his ability to mount a renewed challenge to Fernando Alonso in the remaining seven races of the 2012 F1 season.

The German was sidelined by a repeat of the alternator problems that ended his victory bid in Valencia earlier in the year, and also suffered a similar issue in final free practice at Monza, but engine supplier Renault remains in the dark as to its exact cause. With heat thought to be a contributing factor, and the season closing in some of the warmest conditions of the season, Vettel is naturally concerned that he could become a victim again.

"Obviously, it's not a nice thing to happen," the two-time champion admitted, "It usually helps quite a lot if you are able to finish the race, to get some points, so I'm confident it will improve, but obviously two times this year we've had a problem with the alternator.

"We're working hard on it, [but] it's a bit difficult because, after the failure, you don't know exactly what was wrong, otherwise we would have fixed it after the first time and it would not happen again a couple of months later. But I think we've got a couple of ideas and it should be better in the future."

Having won eleven races en route to his second title in 2011, Vettel has racked up just one success this season, and dropped to fourth in the standings after being stranded trackside at Monza. Despite falling 39 points behind Alonso, and one place behind the winless Kimi Raikkonen, the Red Bull driver insists that the topsy-turvy nature of the 2012 campaign means that bridging the gap is not impossible.

"I think that, after the weekend in Belgium [where he finished second and Alonso retired], it looked much better, but, after last weekend in Monza, it didn't look as good, so I think things can change quickly," he noted, "I don't see any reason why it should change now.

"I think it's easier [to take the title] if you win a lot of races, but it's not impossible [to do it without]. I don't know if there has ever been someone [to do it without winning a race]... I think Keke [Rosberg] won one race [when he won the championship in 1982], [but] it depends what the others do. I think that's the most important thing..."

Vettel's cause has not been helped by Red Bull's RB8 falling short of the dominance displayed by its predecessors, and showing inconsistency in the way it handles from race to race, even if its results remain solid.

"I think that, if you look at all the races that we've had so far, consistency is the most important thing," he confirmed, "I think we always have a car that was good enough to finish in the top five. I think that's pretty consistent, if you look at the championship so far. I think that's what you need and that's what you'll need until the end of the year. Obviously, the more points you score the better it is. We were not in a position to win every race this year, but I think we had a good car and I don't see why it should change in the next couple of races."