The Brackley-based squad had proved McLaren's main challengers for pole in each of the first two grands prix and many in the paddock were tipping them to break their 2012 front-row duck in China, particularly as the Shanghai circuit's long backstraight plays perfectly to the strengths of their car's much-discussed 'double DRS' system.

Although Lewis Hamilton, pole sitter in Australia and Malaysia, was always going to drop five places on the grid owing to a gearbox change, Mercedes nonetheless managed to outpace the McLaren driver on merit with Rosberg completing a storming single flying Q3 run that saw him lap half a second quicker than both the Briton and team-mate Michael Schumacher.

With Hamilton's penalty ensuring an all-Mercedes front-row, Team Principal Brawn admitted he was thrilled with the result - although struck a note of caution ahead of the race by saying the team still wasn't where they want to be yet over a race distance.

"A quite exceptional performance, particularly from Nico today," he told Sky Sports F1.

"We've had a tough start to the season and we know this is not the main event, the main event's going to happen tomorrow, and I think we've still got work to do to replicate what we've been able to do today in the race. But it's a great step.

"I hadn't realised it's our first pole in such a long time, so very proud of that and the whole team is very proud of it. And a good step towards what we're trying to achieve."

Brawn reserved special praise for Rosberg, with the German having come in for criticism at the opening two rounds for qualifying behind veteran team-mate Schumacher.

"That was an exceptional lap," Brawn declared. "I think sector two was a long way ahead of everyone else and really exceptional lap. The sort of Nico we know's there. He hadn't quite managed it in the first couple of races but he came back with vengeance today."

Although Schumacher qualified fourth and third at the first two races respectively, Mercedes came away from the latter round in Malaysia with just a single point on the board in total after problems getting the W03's tyres into the correct operating window in race conditions.

With DRS restricted to overtaking situations only on Sunday, Brawn acknowledges it will be a less potent weapon for the team in lap time but is optimistic they have made progress in improving the W03's overall race performance.

"Well obviously tracks where you've got long straights it's going to be more effective, and that's why I guess we're cautious about tomorrow because it's only available to us when use it in the zones for overtaking," he said.

"But the car's not bad without it. We did a lot of work yesterday, we did some high-fuel work this morning and I think we're starting to understand what we need to do and how to get the most out of the tyres.

"But I think it's going to be quite a tough race tomorrow."