Mercedes GP team principal Ross Brawn has again rubbished speculation suggesting that the team is attempting to hone its car to the demands of seven-time world champion Michael Schumacher.

Brawn, whose eponymous team scooped both F1 world title in its one and only season, has seen Schumacher struggle to get to grips with the WO1 since breaking a three-year retirement to join the rebranded Mercedes outfit. While younger team-mate Nico Rosberg has twice taken the car to the podium, and enjoyed a brief hold on second place in the championship standings, Schumacher's best result of fourth came on the debut of the revised Mercedes in Barcelona, and only after Lewis Hamilton retired from second place two laps from home.

Extending the wheelbase of the WO1 appears to have made the car more suited to Schumacher's driving style, however, leading to rumours that the team was moving its development towards the German and away from Rosberg, who notably struggled in Spain.

"I wish I knew what these requirements are!" Brawn told the official F1 website when the question of favouritism was put to him, "It is pure perception that the car is build around Michael. If you ask me, I would not know what sort of car that would be. A car that responds properly, a car that has a good level of downforce, a car that has power will benefit both our drivers. There is no conscious development to create a car that suits Michael Schumacher, because I don't know what that is. It's hard to do something if you have no idea what it is."

Despite being beaten on a regular basis by Rosberg over the four 'flyaway' races that opened the season, Schumacher remained magnanimous, and it was only in Monaco, when he accused the former Williams driver of getting in his way during qualifying, that any tension between them attempted to surface. Despite that, however, Brawn insists that there is no acrimony in the camp.

"I have not noticed any difficulties beyond the norm," he noted, "When you have two very competitive and quick drivers as we do - and McLaren has - it's more about balancing the situation with the drivers. But the fact is I am more conscious about [the fact] that we haven't won any races yet, conscious that we keep the right spirit in the team

"Yes, after Monaco, there were suggestions that there was some friction between Michael and Nico, but that couldn't be further from the truth. They are working well together and we do it in the right spirit. Sure, some media are dreaming of big headlines with frictions between Michael and Nico, but that would be dreaming up something. I think he's got himself a really tough team-mate, [and] it would be easy for Michael to shine within the team with someone not nearly as quick as Nico - but Nico is very quick and consistent, and Michael has a tough reference point within the team.

"Nico has been strong from race one and it has taken Michael a few races to get back into F1. That helped Nico, and the loss of points in Monaco didn't help Michael, so I don't think that there is a massive significance in [the points difference between them]. I think, in the last couple of races, we probably haven't achieved as good results as we should have with Nico, as he should be much closer to the lead of the championship, but, with the number of points that you can score these days, it is not such a big gap and I think if we get the car right both drivers could be a consideration for the world championship this year."

Asked whether he thought Schumacher should have come back at all - and Jackie Stewart this week added his voice to those who believe the German is damaging his legacy - Brawn insisted that the best was still to come from his long-time friend and colleague.

"I think the important thing is that, apart from Shanghai, Michael has improved at every race," he pointed out, "It is very hard to judge where somebody is going to step back into something - especially F1 - because there is nothing as competitive as F1.

"This sport has the world's best drivers by a large margin. You have seen drivers from other disciplines coming into F1 who have never been able to compete at all. So it is a massive challenge and Michael is enjoying it a great deal. I am really happy with his progress, and his rate of progress is natural. He is fitting very well with the team and he is fitting very well with Nico. I think we are not exactly where we wanted to be and there are still things to come in the future - and, if we get a better car, both our drivers can win races.

"Neither of the drivers is satisfied with the results because we are not winning races. I think he is fine with the progress that he's making because he knew that it would be a massive challenge. He's enjoying it, he is enjoying the motivation that racing is giving him - and, for sure, the team is enjoying working with him."