MADRID (Reuters) - Under-fire coach Julen Lopetegui will still be in charge of Real Madrid for Sunday's 'Clasico' away to arch rivals Barcelona, club director Emilio Butragueno said after an unconvincing 2-1 win over Viktoria Plzen in the Champions League on Tuesday.

Lopetegui said before facing Plzen he could not guarantee whether he would be in the dugout at the Nou Camp against champions Barcelona. He avoided the same question after the victory which ended a winless spell spanning five games but did little to dispel doubts about Real's current form.

Former striker Butragueno, however, said there was no danger the former Spain coach would be sacked before Sunday.

"Lopetegui will be in the dugout at the Nou Camp with absolute normality. In these type of situations it's important to stay calm," he told reporters.

"We hear a lot of rumours but we are dealing with the situation as normal. I hope the team can put in a good performance against Barcelona."

Goals from Karim Benzema and Marcelo put Real on their way to victory although the impressive Czech champions squandered a number of glaring chances before midfielder Patrik Hrosovsky pulled a goal back for the visitors, setting up a tight finish.

When full time came, Real were booed off the pitch by the Santiago Bernabeu faithful, who had also whistled them at the interval. Butragueno said fans needed to show the team more support.

"Madrid fans are very loyal and they think that the team should always be scoring four or five goals but we have to change that tendency," he added.

"In delicate moments we need the support of the crowd to change the situation."

Lopetegui, sacked as Spain coach on the eve of the World Cup for announcing he was joining Real without the national federation's consent, said he was unaffected by the boos.

"I didn't notice anything special, the supporters are sovereign and they treat us very well," he said.

Lopetegui initially avoided the question of whether he would be in charge against Barcelona by saying "that is not a question for me".

When later told that Butragueno had guaranteed his presence at the Nou Camp, he insisted he was not focussed on his future.

"You do not change course in one day but I think today can be a turning point for us," he added.

"We have to keep gaining tranquility little by little."

Brazil defender Marcelo ended the game with a bruised foot and could not play the final minutes but he said he would be okay to face Barcelona.

The left back gave his backing to Lopetegui and gave a pointed response to criticism his side have faced from the media.

"I think it's marvellous that he will be with us against Barcelona, he is a great coach," said the Brazilian.

"It's tough when you lose but journalists are trying to damage the dressing room. Perhaps they are envious because they don't know how to play football."

(Reporting by Richard Martin; editing by Martyn Herman)