Interlopers in Formula One are rarely welcomed when the world championship chase looks set to be a walkover between a favoured few.

He may have got off to the perfect start with a win in the opening Grand Prix in Bahrain, but afterwards Fernando Alonso lapsed into a series of poor finishes until a victory in Germany, controversially gifted by his Ferrari team mate, Felipe Massa, put him back into contention.

It still looked pretty much a fight between veteran Mark Webber and his Red Bull partner Sebastian Vettel and McLaren teammates Jenson Button, the current title holder, and Lewis Hamilton, the champion two years ago.

But now Alonso, the interloper, has broken through and has spectacularly encroached on the top-of-the-table territory.

And he has set alight a championship building up to be the best and most dramatic for 20 years — with Abu Dhabi almost certainly in line to stage a decider finale to remember. Ominously for his fellow battlers Alonso boasts a recapturing of form and finesse, allied to a towering skill behind the wheel, that could carry him through to a third world crown.

His team boss Stefano Domenicali, the pitwall strategist who ordered Brazilian Massa to make way for Alonso at the Hockenheimring, reckons Ferrari and Fernando are on the brink of an astonishing breakthrough for the title. With four races to go Alonso has closed to within eleven points of title pacemaker Webber.

"It is going to be an exciting climax to what has so far been a fascinating championship."

The author is a motorsport expert based in England.