Iran exceeded expectations in the ongoing world event as they stormed into the quarterfinals with four wins, which includes a 4-0 drubbing of pre-tournament favourites Germany.
"It is not going to be easy. Iran is here because of the good things they have done. They won all the four matches. It is one of the best teams -- from defence to attack," Denia said on the eve of the tournament.
"It is the job of the technical staff to find the problem, or the challenges they will face and to adapt it to make sure that tomorrow the team plays well."
Spain are brimming with confidence after prevailing over another European heavyweight France, and the dazzling array of talents give Denia plenty of options.
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When asked about his defence plan, Denia said, "Defence is one of our concerns and there is always room for improvement in the defence. Well, the match against Iran has nothing to do with the matches we have already played.
Asked what sort of match he expects against Iran, he said, "The players you talked about are very speedy and if they get chances they can be dangerous for Spain. Yes, they have done a good job. That's why they are here. They are working as a team."
"We are very relaxed. We know that we have a tough match but there is no doubt that Spain, too, are facing the same situation and have a tough match. We are very prepared and fully ready for the match. Our players are so devoted and looking forward to make the semifinals," Iran coach Abbas Chamanian said.
"We analyse Spain as the next opponent. We hope to have a good performance against an opponent like Spain and emerge successful."
This is the first time Iran have progressed this far, and they will be eager to continue this journey.
With four wins from four matches, scoring 12 goals while conceding just two, Iran have marched in style to the quarter-finals, defeating Mexico 2-1 in their Round of 16 encounter in Goa.