McLaren-Mercedes duo Jenson Button and Lewis Hamilton have hit back at suggestions that Red Bull Racing rival Sebastian Vettel will have a second consecutive drivers' crown sewn up come mid-season in F1 2011 should he continue the way he has begun - but they admit they are presently 'on the ragged edge' merely trying to keep up.

Vettel's dominant Turkish Grand Prix victory in Istanbul last weekend has seen the young German make it three victories from just four starts this year and further strengthen his stranglehold on the world championship battle by extending his advantage in the title standings to a commanding 34 points.

That caused French newspaper L'?quipe to dub him 'Mr. 93 per cent' in allusion to his current points tally and led Italy's La Gazzetta dello Sport to muse that 'if it continues like this, it is no longer a question of if he will win the championship, but when', with F1 legend Niki Lauda agreeing that 'if he keeps it up like this, the season will be over at half-distance'.

Such comments, however, have received short shrift from an angry Button - who blamed a misguided strategy for a distant sixth-place finish in Turkey, after a raft of new parts for McLaren's MP4-26 could not be used following reliability issues during practice - and a rather calmer but equally fiercely determined Hamilton.

"Getting the best out of what we have is the most important thing," stressed the 2009 F1 World Champion, who now languishes some 47 points adrift of Vettel in the standings. "I'm not thinking the title is slipping away already. What's the point in saying that? We might as well f***ing go home as say that. I mean, Jesus Christ guys, let's not make it too negative. We just need more pace, and hopefully we'll turn up in Barcelona next week with that."

As Button visibly bristled, Hamilton - who himself took the chequered flag more than 40 seconds adrift of Vettel at Istanbul Park, where only twelve months earlier he had triumphed - concurred that it would be foolish to write McLaren off so soon, and rubbished notions that the championship could be wrapped up by mid-summer.

"Thirty-four points is a very big gap at the moment," acknowledged the 2008 title-winner, the only man to have defeated Vettel in 2011, in China last month. "He was cruising in Turkey. I've got to be on the ragged edge to try and get every little step I can.

"It's very similar to when [Michael] Schumacher was dominating. Now Sebastian is dominating - pole position in all four races this season, and he's nearly won all four. I don't have a fear [the championship will be over by midway through]; it is possible, but it is also possible we could catch up and overtake them."