Nico Rosberg had admitted that he was surprised that he had the pace to qualify in pole position for tomorrow's Spanish Grand Prix.
The German will start on the front row in Barcelona alongside Mercedes teammate Lewis Hamilton.
Speaking after the qualifying session, the 27-year-old said: "It has just been working really well all weekend, we've optimised everything.
"We're surprised to be that quick, but it was a good qualifying and a good lap in the end, so I'm really, really happy with that.
"The team has been working really hard to be even better, understanding how to get the most out of these tyres. This morning was better so I am a little bit more confident, still tomorrow is going to be a challenge."
Tomorrow's race will be the third consecutive start from pole for Mercedes.
