The biggest mistake that Sebastian Vettel has made in F1 2010 is to have 'underestimated' team-mate and current world championship leader Mark Webber, opines Gerhard Berger, whilst Nico Rosberg is 'on a par' with his Red Bull Racing compatriot and along with Force India's Adrian Sutil, the 'surprise of the season' so far.

With F1 still on its annual mid-summer break, Berger has been running the rule over the current crop of young Germans in the top flight, and he makes it very clear that three of them in particular have impressed him immensely this year.

The Austrian worked closely with Vettel at Scuderia Toro Rosso back in 2007 and 2008 - standing up on the podium with the Heppenheim native when he re-wrote F1 history by becoming the youngest-ever grand prix-winner at Monza just under two years ago - and he agrees with the general paddock perception that the 23-year-old is every inch a world champion in-waiting.

"He is incredibly mature," the ex-McLaren, Ferrari and Benetton ace told Auto Motor und Sport. "It is true he is still making mistakes, but I put that in the category of lacking experience. His biggest problem is that he probably underestimated Mark Webber."

Rosberg, by contrast, has practically run rings around his own team-mate - record-breaking F1 legend Michael Schumacher - at Mercedes Grand Prix over the opening twelve races of the campaign, holding a ten-two lead in qualifying over his illustrious elder countryman and a 56-point advantage in the drivers' standings, causing Berger to muse that with a more competitive car at his disposal, the son of 1982 F1 World Champion Keke Rosberg would be a race-winner at the highest level already.

The 50-year-old had similar words of praise for Sutil, who he confessed he had scarcely rated at all this time twelve months ago but who has progressed in genuine leaps and bounds to transform himself into a regular points contender as Force India has stepped things up a notch.

"For me, Nico is on par with Vettel," he asserted. "He just needs the right car now to begin winning. He has shown this year that he makes very few mistakes, that his set-up is usually right and that he is mostly ahead of Michael Schumacher. If Rosberg and Vettel were sitting in identical cars, I would not know who to put my money on.

"Last year, I was laughing at [Sutil]. I would never have believed he has this much potential. His speed is tremendous, and his mistakes have reduced dramatically. For me, with Rosberg, he is the surprise of the season."

The one German to have caught Berger's eye to a lesser degree, finally, has been Williams F1 rookie Nico H?lkenberg, with the ten-time grand prix-winner arguing that the 22-year-old needs more time to develop before a full assessment can be accurately made - whilst conceding that in team-mate Rubens Barrichello, he irrefutably has the perfect teacher.

"He is in a learning phase," he acknowledged. "He makes many more mistakes than Vettel and Rosberg did when they began, but Sutil was the same. I think H?lkenberg's mistakes are normal for a first year. If everything goes right, he is almost at the level of Barrichello - and that's a compliment. Barrichello is certainly the best man of the second league, and with his vast experience he doesn't make mistakes."