Spain midfielder David Silva said Sunday’s last-16 clash against World Cup hosts Russia would be as tough as facing five-time winners Brazil.
The Manchester City star was part of Spain’s title-winning squad in 2010 in South Africa, and his side will be clear favourites in Moscow.
However, they have yet to hit top gear in the competition and won just one of three group games, defeating Iran 1-0 while drawing with Portugal and Morocco.
“I think that in a World Cup any opponent is tough. We saw this in our own group, it was very hard for us to win,” Silva said on Saturday.
“Now we’re playing against Russia and I’m sure it’s going to be extremely difficult, as if we were playing against Brazil.”
Spain will need to tighten up a defence that leaked five goals in the group phase, with Russia the joint-second leading scorers in the competition.
“We must minimise the mistakes,” Silva said. “In such difficult games if we give away goals through mistakes, things are going to be very difficult.
“We need to defend much better and the smallest mistakes can send you back home.”
Silva, who has started each match in Russia so far, has been one of the targets for criticism.
The 32-year-old will look to let his feet do the talking as Spain try to take advantage of what appears a favourable draw.
“The criticism has been talked about a lot,” he said. “We are professionals, we have to focus on trying to do our best so we can change people’s opinion. It isn’t always deserved but we’re used to it.”
Spain have a terrible record against host nations at major finals – they have never won in eight attempts – but coach Fernando Hierro is not worried by past failures.
“Statistics are made to be broken,” Hierro said. “Why are we always looking backwards? We’ve had three games here but we’re going to look at what happened 10 or 15 years ago?
“It’s about what happens at 5:00 pm tomorrow. Al the rest is irrelevant and that’s what we need to focus on.”
Spain were held by Russia in a 3-3 draw in a friendly last November in Saint Petersburg.
The last competitive fixture between the sides came at Euro 2008, where Spain beat Russia 3-0 in the semi-finals before going on to lift the trophy.
“We have a very clear plan in mind. We know what Russia represent, we know their qualities and we have a lot of faith in our players,” said Hierro.
“It’s a difficult team, physical, good at set pieces and very tall. There’s lots of variety and we’ll have to find their weak points.”
“Tomorrow we’re starting a new tournament,” he added. “We’ll see who’s on top after 90 minutes, the best will stay, or sometimes the best goes home as well.”