Rosberg 'must try to catch' Hamilton - Lauda

May 6 (GMM) Nico Rosberg is facing a tough task to get back on terms with Lewis Hamilton.

Earlier, F1 legend Sir Stirling Moss insisted that Hamilton, although a double world champion and on-form championship leader, is "not yet" a great.

But he is quoted by the Swiss newspaper Blick: "Hamilton is in another league. Rosberg simply has no chance."

Even Rosberg's own boss, Mercedes team chairman Niki Lauda, thinks the German has one of the hardest jobs in all of formula one at the moment.

"Hamilton is driving like an extra-terrestrial," the F1 legend is quoted by Austria's Kleine Zeitung newspaper.

"At the moment he is on a run where everything is perfect. He makes no mistakes and does lap times that no one else can do," added Lauda.

As for Rosberg, "Of course he is frustrated. But Nico must try to catch him."

For Hamilton, it might be said that the bigger threat now is a German who wears red.

But Lauda said Mercedes remains well positioned to take on Sebastian Vettel and Ferrari, especially as it is yet to spend a single in-season 'token' to upgrade its power unit.

And "Maybe Ferrari has used more tokens than us," he speculated.

In Spain this weekend, added Lauda, the real eyes will be on the respective teams' aerodynamic upgrades.

"Barcelona is one of the most challenging tracks there is," he said.

"When your car wins there, you can assume it will also be good for the next three or four races."