Cesar Azpilicueta is convinced Spain have what it takes to contend for the World Cup title despite a shaky start and the dismissal of manager Julen Lopetegui on the eve of the tournament.
The 2010 world champions qualified for the last-16 as winners of Group B ahead of Cristiano Ronaldo's Portugal, and face hosts Russia in Moscow on Sunday.
Spain are unbeaten in 23 matches, a run dating back to Euro 2016, but the Spanish federation's decision to sack Lopetegui after he accepted the Real Madrid job threatened to derail their campaign.
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"It's clear that it's an unusual circumstance that doesn't happen often, but that's what happened and you have to take things as they are," Chelsea defender Azpilicueta said in an interview with AFP.
"You can't shy away, you have to accept the reality. We must do our work in the best way we can and go as far as possible."
Fernando Hierro, the former Real captain who played 89 times for Spain, was appointed to replace Lopetegui despite limited previous coaching experience.
Hierro, 50, spent a single season in charge of second division Spanish outfit Oviedo, but Azpilicueta is confident he can handle the international role.
"Fernando has shown great enthusiasm, he's very involved. He had to face up to this situation and he is giving everything he has to help us, to improve the team," he said. "I have no doubt we're going to achieve our goal.
"The dynamic is very good, very similar to that of the last two years," he added. "The group is united, with a desire to grow, and thirsty for victory. Each coach has their own way of working but there haven't been any big changes."
Ronaldo scored a hat-trick in a thrilling 3-3 draw with Portugal in their opening game, while Spain's backline was breached twice more by Morocco.
"It's true that we've scored goals but we've also conceded a lot of them too," said Azpilicueta. "We're professionals, we have clear minds and we know we can offer more.
"We're an offensive team, with lots of attacking players, and we've always had this problem. When you get lots of players up front, sometimes a counter-attack can take you by surprise and lead to a chance for the opposition.
"We must work on this point and regain our solidity."
Russia will have the backing of the vast majority of the 80,000 fans at the iconic Luzhniki Stadium in Moscow, and Azpilicueta is aware of the problems the home side can pose.
Spain drew 3-3 with Russia in a friendly in Saint Petersburg last November, a game in which Krasnodar forward Fedor Smolov netted twice.
"They're playing at home and it's clear we don't have any room for error," Azpilicueta said.
"We have to give our all from the first minute to the last. Russia are a solid team physically with quality players and we suffered against them in a friendly in Saint Petersburg.
"Aside from their last match, they've won with a certain ease and it will be a difficult game."