SEPANG, Malaysia, March 23 (Reuters) - Sebastian Vettel tip-toed through the early stages of qualifying for the Malaysian Grand Prix on Saturday before blasting to pole position at a rain-hit Sepang Circuit with a well-timed change of tyres.
Red Bull's triple world champion secured the 38th pole of his Formula One career after opting for a new set of intermediates on a drying track to hold off the twin Ferrari threat of Felipe Massa and Fernando Alonso, who adopted a similar strategy.
After the disappointment of Melbourne a week ago, when he dominated qualifying in the season-opening race before finishing third behind Kimi Raikkonen's Lotus and Alonso, Vettel was careful with his tyres on Saturday.
"It was an interesting qualifying session. We knew that rain was the on the way and to be honest we expected some at the beginning of qualifying but it didn't come," he told reporters.
The German drove conservatively in the early phases of qualifying and was ninth towards the end of the second phase when the first drops of rain prevented anyone from improving on their times and the top 10 advanced to the final round.
"Obviously I think we had a bit of a different approach to other people. Q2 was quite on edge I would say, so probably the rain helped us a little bit. Otherwise I think we would have had to go out again. But in that case it was just enough to go through to the final phase," he said.
"Then in Q3 with the circuit drying, it was clear it was better to change tyres.
"We confirmed that pretty early. I think we did the right thing. Very tricky because you don't know if there's more rain coming or not, but we took the decision."
The rain held off and Vettel eased ahead of early pace-setter Lewis Hamilton's Mercedes before watching Massa claim second place and Alonso third, although both Ferraris were almost a second behind.
"I'm a bit surprised by the gap but it was a decent lap and I was very happy obviously. It was quite tricky because some parts of the track were still wet and others were dry but overall a very good session for us," he added.
"We managed to save some tyres, which could be crucial tomorrow, so we'll see what we can do."
Team mate Mark Webber will start in fifth place but the Australian cut a dejected figure after he was unable to set a final flying lap as he ran out of time due to a misunderstanding.
"I think we got out of the car what we could have done, on the laps when I was pushing," he said.
"Then we basically didn't push when the track was at its quickest because we thought we had a bit more time - well, I thought I had more time and more laps to play with.
"At the end, I got the red light when I went over for the last lap. Frustrating, that's the way it goes sometimes. We're fifth and I can still race from there." (Editing by Alan Baldwin)