New Mercedes motorsport boss Toto Wolff admits that 'the only thing that happens is lap time' after the team launched the new F1 W04 in Spain.

The Brackley-based squad heads into 2013 with a new-look driver line-up after signing Lewis Hamilton to partner Nico Rosberg, with the focus on challenging for the title after a tough year in 2012.

Hopes are high that the technical restructuring that Mercedes has undertaken over the past 18 months will finally come good this season, with the new technical team having a direct input into the new car.

Speaking after the car was revealed at Jerez ahead of pre-season testing, Wolff said he was impressed by what he had seen from his time with the team thus far but insisted that it was results on track that would be key during the year ahead.

"The first laps for a new car are always filled with emotion and today was no exception," he said after the car completed a brief run on track with Rosberg at the wheel. "It is even more meaningful when the car is a Silver Arrow: Mercedes-Benz has a long tradition of racing success and this is something we are proud to represent and determined to live up to.

"In the fortnight since I joined the team, I have been impressed by what I have found. The people are highly motivated, open-minded and determined to succeed. Our drivers are hungry for success, too, and it will certainly be fascinating this season to see how Nico and Lewis perform together.

"Ultimately, though, Formula One is very straightforward and the only thing that counts is lap time."