EDEGEM, Belgium, June 10 (Reuters) - The Yugoslavs say they view their Balkan derby against Slovenia as their toughest match in Euro 2000 group C - simply because it is their first.

Never mind that Yugoslavia must face tournament favourites Spain on the final day of the group phase and in-form Norway in their second match.

Asssistant coach Zoran Filipovic says the clash with Slovenia, the surprise team in the qualifiers for Euro 2000, will be every bit as tricky.

'I don't agree,' Filipovic told a news conference when it was suggested that Tuesday's match in Charleroi would be the easiest of the three.

'I think it will be the most difficult for us because it is the first. It's very important for us to win this match although of course it won't be a catastrophe if we don't.'

Yugoslavia arrive in Belgium following an Asian tour for which their coach Vujadin Boskov has been heavily criticised.

Some of the players have reportedly complained of exhaustion after a four-match tour which culminated in a friendly in humid Hong Kong just seven days ago.

The players had just two full days at home before packing their bags for Belgium and although they undoubtably have the talent to go far in the competition, some observers say they will need a couple of matches to find their stride.

'Slovenian football is of the same school as Yugoslavian football and in many ways this match is the most important for us,' Valencia defender Miroslav Djukic said.

'We're feeling fine physically,' he added when asked about effects of the Asian tour. 'We're fit and ready for the start of the tournament.'

Goalkeeper Ivica Kralj, who plays his club soccer up the road at PSV Eindhoven, said he knew some of the Slovenians from their time together at Partizan Belgrade and FC Porto.

'We probably have a small advantage over them as a squad but we have to prove it on Tuesday,' he said.

Filipovic said the Yugoslavs would play a practice match on Saturday evening against FC Katalen, a local side founded by immigrants from the Spanish region of Catalonia.

Celta Vigo defender Goran Djorovic, Deportivo Coruna midfielder Slavisa Jokanovic and Benfica's new signing Ivan Dudic would all sit out the session due to tiredness but all would be fit to face the Slovenes, he said.

'The most important thing is that we don't take it easy in the first match of the tournament,' midfielder Vladimir Jugovic said.