Haug concedes Mercedes GP will need more time to succeed in Formula 1

"Compared to Red Bull, it took five years to build up that system and the first race was won by Sebastian Vettel in a Toro Rosso, which is a similar car," Haug told AUTOSPORT.

"With all respect and credit to them, it has taken time. We need to accept that it needs building up time.

"I'm not speaking about two years from now, but a longer period of time. If you achieve it [success] in less than five years without throwing money at it, which teams did in the past, then you are really very special."

Mercedes returned to Formula 1 with its own team last year, having taken over the Brawn GP squad, which had won both titles in 2009.

Despite the success of that year, Mercedes has been unable to repeat that kind of performance and, although it had high hopes for this season, the team has struggled to be competitive, having not finished on the podium in 2011.

Haug conceded the expectations ahead of the start of the year were simply too high.

"You could argue that our anticipation from the beginning was not exactly spot on," he said, "and we had this cooling issue we had to concentrate on resolving, so once the train had started and you need to run behind the train, then it's quite difficult [to catch up].

"But in a way, if we were in the same position it would be worrying if the gap became bigger and bigger. There is an intense rhythm of development. Speak to Ferrari, speak to McLaren, speak to Red Bull and they will admit that they have upgrades at each and every race."

He also believes that one what he reckons to be the strongest field in F1 history is making Mercedes's job to catch up an even harder-than-usual task.

"We've certainly this year, had it tough, a tough group with very strong competitors, probably stronger than ever in the history of Formula 1," he added. "We have three teams that have won races, McLaren was in a position to win more, Ferrari was in a position to win more.

"Of course, Red Bull won most of them, but both of them did quite impressive catching up which depended at times on the nature of the circuit and we have positioned ourselves as number four."

Haug, however, is adamant that Mercedes has closed the gap on the leading teams, even if its not reflecting in the results.

"We have had a very difficult start, especially over the first two races, just, we have been on our left foot, and I think it speaks for the team that in the third race, which is different from the other grands prix, that we were leading for 14 laps.

"It is very difficult if you're carrying a deficit into the season. I think there are some interesting figures we can provide you with. In Australia, the difference to the leaders was 2.3 per cent, in Malaysia 2.0 per cent, in China 1.0 per cent, in Turkey 0.6 per cent - more than half a second - in Spain 2 per cent, Monaco 1.5 per cent, Canada 1.1. per cent, Great Britain 1.1 per cent, Germany 1.3 per cent.

"Anyway, I think it's stabilised in a way. The rhythm that the front cars are having is changing, but we have at least kept the same margin. The target is to start on a higher basis and then go from there.

"I think the most important point is that we are focussed, have a long road ahead of us and we are working very hard."