Spain coach Vicente Del Bosque does not feel his side have gained any advantage by securing a last 16 showdown with Portugal rather than five-time world champions Brazil.
Spain's 2-1 win over Chile in Pretoria saw them replace the South American side at the top of Group H, but with both nations still going through.
Del Bosque said: "Portugal concern me. We've seen how they controlled the game against Brazil, hitting them on the counter-attack. Portugal are going to be a very tough side. I take no satisfaction from the fact we're up against Portugal instead of Brazil. They are both great national teams."
Spain at least go into the clash with Portugal battle-hardened by their experiences in the group stages.
The Spanish came into the World Cup rated by many as favourites to clinch the title, but those lofty expectations were tempered considerably when they lost their opening match to Switzerland.
Del Bosque's men have got themselves back on track with victories against Honduras and Chile, although it could have been a different story against Marcelo Bielsa's side.
Chile looked to be gaining the upper hand when they helped gift Spain the lead in the 24th minute.
Goalkeeper Claudio Bravo needlessly raced out of his goal and kicked his clearance straight at David Villa, who fired straight into an empty net from 40 yards out. Spain then doubled their lead just before the break through Andres Iniesta, while at the same time Chile were reduced to 10 men when midfielder Marco Estrada was shown a second yellow card for what looked an accidental trip on Fernando Torres.
It was harsh on Chile to find themselves in such a position at the break, and although they pulled a goal back just after half-time, they rarely looked like getting another goal. Iniesta, who was named man of the match, admits Villa's goal was crucial.
"David's goal was very important for us. It came at a difficult time where we weren't finding it comfortable," Del Bosque added.