Spain's coach Luis Aragones thought his side were fortunate to beat Russia 4-1 in their opening Group D clash on Tuesday.
David Villa grabbed an impressive hat-trick before substitute Cesc Fabregas headed a late fourth, but the final scoreline flattered Spain, according to their veteran boss.
He said: "It looks as if this was an easy win but it wasn't like that.
"Physically Russia are a very strong side and they pressed us hard in the first half. I thought we were a bit lucky.
"We scored on the break and, just when they were putting us under heavy pressure, we got the second.
"However, we are very good at playing the ball around when we have control and I'm very happy with the whole group.
"This win will help us psychologically. A 4-1 win gives us a big boost and it is a win that will not just help us but is also good with a view to our next opponents because they are going to look at us with more respect.
"We must not carried away, however, as in four days we have a game against a difficult Sweden side."