MONTMELO, Spain - Lewis Hamilton and Mercedes were in a class of their own again in qualifying for the Spanish Grand Prix on Saturday, while struggling four-time champion Sebastian Vettel stalled and was demoted on the grid.
Hamilton edged teammate - and main rival - Nico Rosberg with a late lap of 1 minute, 25.232 seconds on the sunny and dry Barcelona-Catalunya circuit for his fourth pole of the Formula One season and 35th in his career.
Rosberg, the overall leader, came in second at 0.16 seconds behind to set up another driving duel. Hamilton has won the last three races right in front of Rosberg, with the rest of the field far behind.
"Nico was really driving well though practice and qualifying," Hamilton said. "I didn't know if I was going to get it, but right at the end I had to eke out absolutely everything I could get from the car."
Vettel's Red Bull has left him stranded twice in two days. First it rolled to a halt during Friday's first practice session, and it failed him again early in the third period of qualifying.
Vettel was left 10th in qualification, but he will start from 15th on the grid after Red Bull incurred a five-place penalty for replacing his car's damaged gearbox. Regulations require gearboxes to be used for at least six consecutive races.
As Vettel's troubles mounted, new partner Daniel Ricciardo finished with the third fastest time ahead of Williams' Valtteri Bottas and Lotus' Romain Grosjean.
Fernando Alonso, last year's winner here, could do no better than seventh place, right behind Ferrari teammate Kimi Raikkonen.
Hamilton complained to his team early in the day that they "made the car worse" after minor changes to try and improve on its already commanding performances from Friday, when the British driver dominated both practices.
"It was a real handful for me," Hamilton said. "It was back to square one. I was a half second behind Nico but at the end I did it by the skin of my teeth."
Rosberg wasn't afraid to show his disappointment.
"I don't particularly enjoy coming second to Lewis," he said. "But all it takes is a good start tomorrow and I am in the lead again."
Hamilton and Rosberg are poised to dominate a fifth straight race after sweeping the first four and taking all five pole positions.
That dominance was acknowledged by Ricciardo.
"We are best of the rest. But that is not good enough, we are still a second off," the Red Bull driver said. "We have made some improvement, but they, being Mercedes, have done so as well. Even with a different strategy in the race, it is going to be difficult to make up a second each lap."
In 23 races at Montmelo, 15 pole-sitters have gone on to victory, while only two drivers have won when starting from third place or lower.
Red Bull appeared to have Vettel's car back in a good enough condition to compete, but its transmission acted up at the start of the third qualifying period when he pulled out of the garage, and by the third curve his car came to a halt.
Vettel told his team by radio, "I have no drive, I'm sorry, I have no drive" before he jogged back to pit lane while waving to fans.
Ferrari showed no sign that the three-week break before the European races had paid off in improvements.
"This wasn't a good qualifying session," Alonso said. "But the outcome was more or less what we could have expected on a difficult weekend."
Less than two minutes into the session, Pastor Maldonado crunched the right wheel of his Lotus when he lost control coming out of a right-hand turn and slammed into the wall on his third lap. Maldonado, who won here in 2012 with Williams, emerged unscathed from the car before it was hauled away.
Toro Rosso's Jean-Eric Vergne will start the race from the back of the pack after he was docked 10 places for breaching safety regulations on Friday when a wheel flew off his car. He finished qualifying in 16th place.