Ralf

	Michael

Schumacher told a news conference at Ferrari's winter retreat in the Dolomites: "Obviously there is a little question mark concerning McLaren due to them changing tyre company -- we don't know how quickly they can adapt to that.

"But these two teams (Williams and McLaren) are the two big threats as usual except that (Williams) is in a much better position, for me, this year than they have ever been.

"Although they have put their own chances on a lower level, so as not to build up the pressure too much I think they are going to be very strong and we are going to face a lot of difficulties from them," said the German.

Schumacher's closest rival last season was McLaren's David Coulthard, though the Scot finished a distant second.

With Finn Mika Hakkinen having a year out from the McLaren squad and being replaced by compatriot, 21-year-old Kimi Raikkonen, Coulthard is certain to be the team's top man this season.

But Schumacher expressed some doubt as whether Coulthard would get faster in his new role.

He said: "I don't know if he can or can or cannot. David remains David -- he is a strong racing driver and he is going to be a challenge to me no doubt.

Interesting question
"That is why I mention McLaren. How much is going to be David how much is going to be Raikkonen is going to be an interesting question to be answered."

The internal ranking within the Ferrari team was addressed by Schumacher's teammate Rubens Barrichello on Wednesday, with the Brazilian claiming everything at Ferrari is geared up for Schumacher.

But the world champion said: "I don't think this is correct at all.

"Rubens is a very important part of our team, honestly, and from my point of view when we work together what I can see myself is that the team supports him as much as me, there is no doubt about that.

"Ferrari is such a big team they have the capacity to deliver two equal cars."

The four-time world champion admitted that he had clashed with Barrichello in the past.

"Sometimes there are problems I think that to get to know each other and sort out opinions you need to have an argument and we have had that in the past."