Mercedes driver Nico Rosberg says Mark Webber was a tougher team-mate than Michael Schumacher has been.

Rosberg made his Formula One debut alongside Webber at Williams in 2006 and has partnered Schumacher at Mercedes for the past two years.

In his four tough years at Williams, he also drove alongside compatriot Alex Wurz and Japan’s Kazuki Nakajima.

Mercedes was formed after the championship-winning Brawn team was disbanded at the end of 2009 with Rosberg leaving Williams to join the outfit and Schumacher coming out of retirement.

Asked by Germany’s Sport Bild who his toughest team-mate has been, Rosberg was unequivocal: “Mark Webber in 2006, then Michael.”

Rosberg has beaten Schumacher in the two years they have raced together at Mercedes, finishing seventh both seasons to Schumacher’s ninth in 2010 and eighth last year.

Meanwhile, Webber has completed a full race simulation in the 2012 Red Bull car during testing in Spain.

After the team worked to sort out a gearbox issue, Webber was optimistic about the RB8’s potential ahead of next month’s Australian Grand Prix.

“All in all, it wasn’t a bad day at all,” Webber said.

“Not the smoothest of mornings and we didn’t get too many laps done there but, in the afternoon, the race simulation went OK. We’re still learning plenty.”

Webber said there were “loads of positives to look at”.

“We’re a very ambitious team, so we’ll keep working on that,” he said.

AAP rg/a