Red Bull's Sebastian Vettel on pole for Turkish GP

World champion Sebastian Vettel was uncatchable in Turkey, capturing his fourth pole in as many races this year.

The German Red Bull driver set his fastest lap of one minute 25.079 seconds, then sat in the garage to watch his rivals fail to match him.

Mark Webber joined his team-mate on the front row, 0.405secs behind, with Nico Rosberg third for Mercedes.

McLaren's Lewis Hamilton and Jenson Button were fourth and sixth, sandwiching Fernando Alonso's Ferrari.

Vettel has looked unstoppable in qualifying all year but this time he knew it as he and Webber opted not to do second runs in qualifying, leaving their rivals to try - and ultimately fail - to better Red Bull's times.

The world champion had already proved how unshakeable he was, immediately getting up to speed on Saturday after sitting out practice on Friday afternoon because of a heavy crash.

Hamilton queries McLaren tyre call

"We were there from the beginning and I am very happy. I like the track, which helps and it was nice to see that after not many laps I was able to find the rhythm," he said.

"Both Mark and myself decided to skip the second run, and it is a strange feeling because the others are on track and there is nothing you can do."

BBC F1 commentator Martin Brundle said: "There is no stopping this young man.

"Whichever way you cut it, that was an incredibly quick lap time.

"Vettel has become the first man since McLaren's Mika Hakkinen in 1999 to capture the first four poles in any season."

After a dismal run of form in qualifying, Webber will be encouraged to find himself installed as Vettel's closest challenger for the first time this season.

The Australian, who battled from 18th to third in China  , also chose not to go out for a final run.

Webber took pole in Turkey last season but was spectacularly taken out by his team-mate when Vettel challenged him for the lead, but team boss Christian Horner said he did not expect a repeat on Sunday.

I'm not happy at all to be so far off

Michael Schumacher on his eighth place on the grid

"They know what happened and they learn their lessons," Horner said. "They are here to get the best result for the team."

Mercedes, who ran a new rear wing and brake ducts in Istanbul, had been hanging onto Red Bull's coat tails during final practice on Saturday and Rosberg underlined the team's improvement by claiming third.

Rosberg qualified just half a second behind Vettel with team-mate Michael Schumacher close behind in eighth.

"I'm not happy at all to be so far off," Schumacher said. "We couldn't reproduce what we did this morning.

"The more I pushed the more things went wrong and I had no grip left."

Mercedes team principal Ross Brawn said: "It was a great effort by everybody, I'm really pleased."

However, he did warn that the German team were still some way from fighting at the front.

Sixth-placed Button blames balance

Hamilton, who won the last race in China, lines up alongside Rosberg on the second row after finishing 0.546secs off the pace.

"It's not pole position but it's better than nothing," said Hamilton. "I would have hoped for a little bit better.

"We are in the fight. We don't have an extra set of soft tyres for the race and we've seen that Mercedes and Ferrari have picked up their pace."

Button rued problems with his car's handling but, like Hamilton, was confident the McLaren would be more competitive in the race.

Ferrari ran a raft of updates in Turkey - including new front and rear wings - in attempt to close the gap on Red Bull and McLaren

But the Italian team had to work furiously before qualifying to solve problems on both Felipe Massa and Alonso's car.

The engine was changed in Massa's Ferrari while Alonso's car was given a thorough check after he lost power in final practice.

Alonso lines up in fifth with Massa, a three-time race winner in Istanbul, starting in 10th after he failed to go out for a timed lap in the final phase of qualifying.

"Obviously we were still far away from pole position - 0.8secs - but in China we were 1.4secs so we made a step forward," said Alonso.

"In the race in Malaysia we were close to the podium, and in China Felipe was close, maybe in Turkey it will be Ferrari's turn."

Vitaly Petrov qualified in seventh with team-mate Nick Heidfield ninth.

Scot Paul di Resta, who is preparing for his first race in any category at Istanbul Park, lines up in 13th for Force India.

Kamui Kobayashi was the midfield runner who joined the Team Lotus, Hispania and Virgin drivers in dropping out of the first phase of qualifying.

The Japanese driver failed to complete a single lap for Sauber, but will start in 24th after the stewards took into consideration his times in free practice.

"The engine stopped but we still don't know the problem," explained Kobayashi. "It is really bad luck.

"It'll still be a nice race. Performance-wise we are not too bad."

Kobayashi did not fall foul of the 107% rule - which prevents cars which are 107% slower than the leading time set in the first phase of qualifying from starting the race - because he set a suitable lap time during practice.

Kovalainen was encouragingly just half a second shy of the midfield pack for Team Lotus, who are planning a big upgrade for the next race in Barcelona.

"We are on the right track and we just have to keep pushing," said Kovalainen. "We are nearly there.

"The race pace is even better so I'll only be going forwards on Sunday instead of backwards."