MONACO -- Nico Rosberg put himself in position to win the Monaco Grand Prix and emulate his father's achievement of 30 years ago.
Rosberg clinched his third consecutive pole and a fourth straight for Mercedes in Saturday's qualifying, finishing ahead of his teammate Lewis Hamilton and defending champion Sebastian Vettel.
In 1983, Rosberg's father -- the former world champion Keke Rosberg -- took the checkered flag in Formula One's showcase race.
However, the younger Rosberg seems more interested in whether his car can go the distance -- having fallen short in previous races -- than securing a father-and-son double.
"It's always nice to hear statistics like that, but it doesn't change much for tomorrow," said Rosberg, who won his only career GP from pole at the China GP last year and whose best result this season was fourth in Malaysia.
Rosberg has reason to be cautious, because Mercedes also took the front row in qualifying at the Spanish GP two weeks ago -- only to fall way behind in the race, with Rosberg more than one minute behind race winner Fernando Alonso in sixth and Hamilton a full lap behind in 12th.
"In Barcelona we were struggling lot in the race and I finished 70 seconds behind the winner," Rosberg said. "We're improving step by step, but there are still a lot of questions remaining. It's still our weakness."
As long as Rosberg starts well, he shouldn't have those problems in Monaco, which is the hardest circuit in F1 to overtake on.
But Vettel, who was fourth last year despite being ninth on the grid, has not ruled out his chances of victory.
"I still think we have a great chance from P3 (on the grid)," the German said. "I don't know. There are a lot of laps here, 78. If all goes well hopefully the Mercedes will struggle, but we can't rely on that. We have to look after ourselves first."
Vettel qualified ahead of Red Bull teammate and last year's winner Mark Webber.
Red Bull were 1-2 with just over one minute remaining in qualifying, but Mercedes again showed it is near-untouchable on one-lap speed, despite tricky weather conditions with the track damp from frequent bursts of rainfall around lunchtime and again early into the afternoon session.
"It was changing so much (that) you have to be on the right tires at the right time," said Rosberg, who clocked one minute 13.876 seconds. "It definitely could have been easier. The conditions were all over the place, and then it started drizzling again so the lap times got a lot slower."
Surprisingly, Hamilton was not pleased with his run -- although perhaps that was more to do with the fact he was again beaten by his teammate.
"I've been struggling all weekend and my pace has been slacking. I've struggled with the car and this is the first time that's happened since 2005," said Hamilton, who won the F1 title in 2008. "It's been a difficult weekend, so I'm happy to have been able to lock out the front row for the team. It's been a massive improvement for me."
Hamilton is baffled as to why Rosberg keeps beating him.
"It is a new situation for me, one that I seem to be dealing with pretty well," Hamilton said. "Already to be second is a bit of a blessing for me to consider how slow I was in practice. Hopefully in the next couple of races we will see (an improvement).
Red Bull won the last three Monaco GPs -- all from pole -- but it was still a good afternoon for Vettel because he finished ahead of his two main rivals. Kimi Raikkonen starts from fifth place while Alonso is sixth and the Spaniard needs circumstances to go massively in his favour.
Raikkonen is only four points behind Vettel and Alonso cut the deficit to 17 after winning in Barcelona.
"I'm happy there's not a Lotus or Ferrari ahead," Vettel said.
Ferrari driver Felipe Massa goes from the back of the grid. The Brazilian was unable to start qualifying after a heavy crash in the morning's third and final practice session, from which he escaped unharmed. He would have incurred a five-place grid penalty anyway because Ferrari had to fit a new gearbox following his crash.
"I think for sure it is the worst track to have this problem. But I think we need to be positive for tomorrow," Massa said. "It's very difficult to overtake here, we know, but anything can happen here in a race. Maybe the safety car comes out."
Massa, Frenchman Romain Grosjean and German Adrian Sutil had all crashed in practice.