Spain midfielder David Silva has warned his teammates that they cannot afford to underestimate World Cup hosts Russia in Sunday's last-16 tie.
The 2010 winners were criticised back home for their performances in the first round, despite eventually coming out on top in a group that contained Portugal, Iran and Morocco.
La Roja could only manage one win from their three matches, which included a late 2-2 draw with Morocco in their final outing on Monday evening.
Silva, among those to have been vilified, admits that it is important Spain cut out the errors if they are to remain on course for another World Cup crown.
"There's been a lot of talk about the criticism, we're professional and have to dedicate ourselves to playing and changing opinions," he told reporters. "Sometimes the criticism isn't deserved; I've been here for 12 years and I'm used to it.
"The first and second games were good but the opposition count too. The group was tough and we have to minimise mistakes. We have to be focused and defend well. At a World Cup the smallest thing can send you home.
"Any opponent is tough, it takes a lot to win. Russia will be very difficult and it will be the same as if we were playing against Brazil."
The last win by either Russia or the USSR in a World Cup knockout game was the 1966 quarter-final against Hungary.
