Michael Schumacher [Images] remains a formidable opponent even if Ferrari [Images] appear to have gone off the boil, the world champion's Formula One rivals warned on Wednesday.

"I think it is quite clear to everyone that it has more to do with the tyres than anything else," said Red Bull's David Coulthard when asked at the Monaco Grand Prix about the decline of once-dominant Ferrari.

"It's a long season and you can only write the 'downfall of Ferrari' chapter once you get to the end of the season if they are still struggling.

"I don't think he [Schumacher] is losing his edge."

Ferrari, constructors' champions for the past six years, won 15 of last season's 18 races but have now gone six in a row without success.

Schumacher, winner of the last five titles and seven in total, is 34 points adrift of Renault's championship leader Fernando Alonso [Images] after five races.

"I think that period [of dominance] is maybe finished for Ferrari," said Renault's Italian Giancarlo Fisichella. "I think they still have a very good package ... I think they are there."

Alonso agreed.

"Every race is getting more difficult for them but I think Michael still has a chance to win everything, also Ferrari for the constructors' championship," said the Spaniard.

"After the dominant position they showed in the last couple of years you always think that Ferrari will come back.

"I think if Michael wins two races in a row, or one race, the question will be if Michael is in the fight for the championship.

"At the end, I think they will be there for sure."

The German, at 36 the oldest driver in Formula One, has an uphill task in Monaco this weekend after retiring from the last race in Spain with tyre problems.

That result means he will have to run early in Saturday's first qualifying, when track conditions are less favourable.

Overtaking is extremely difficult on the Mediterranean principality's tight street circuit, where Schumacher has won five times, and a good grid position is crucial.

Despite that, only four drivers have won in Monaco from pole position in the last 14 years.

"I have recently done races from much worse starting positions, from 13th at Imola and eighth in Barcelona, and I have made up quite a lot of positions," said Schumacher.

"And even here I have made up positions if you have the right strategy," added the German. "It's important to be in touch with the front, it's not mega-important to be on pole.

"It's obviously more difficult after Barcelona but I haven't given up. There are 14 races to go, 140 points for me to catch and we'll see if we can or not."

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