The world champion secured his second pole position of the season by nearly a full second ahead of Ferrari's Felipe Massa in the rain-hit qualifying session.
All drivers ended up using the intermediate tyres in Q3.
Vettel had been ninth fastest in Q2, nearly a second behind pacesetter Nico Rosberg's Mercedes.
The world champion admitted he was not sure if he had the pace to match the German's time.
"It is difficult to say," Vettel said when asked if he had the pace to be on pole in the dry. "The timing helped in that regard.
"I think we had pace to get there [Q3] on our own, but it helped more in regards to saving a set of tyres for tomorrow. We felt competitive all weekend, felt happy in the car.
"The pace set in Q2 was fast, a pretty good lap and I don't know if we had a strong [enough] car. Whether it was enough to beat that time or not I don't know."
The Red Bull driver said his team had been prioritising saving tyres for the race given its struggles with the durability of the Pirelli rubber.
"It is difficult to know how quick you go if you try not to go 100 per cent," he added. "It's fair to say we tried that. It was quite tight in qualifying.
"In dry conditions I crossed the line and thought maybe it was not quick enough as we were running quite late. Once it was enough, we came in to save the tyres."