El Guaje's goal helped secure a passage to the quarter-finals...
The new Barcelona signing scored the only goal of the game in the second half to book the Spaniards a place in the last eight against the South Americans, who beat Japan on penalties earlier on Tuesday.
"We know what has occurred in previous matches, like against Switzerland," Villa told AS. "Paraguay will be tougher than Portugal because the side has reached the quarter-finals for the first time."
The 28-year-old, who netted his fourth goal of the competition, then reflected on the victory, admitting that Spain suffered at points in a tough 90 minutes, despite deserving the win.
"I am very happy for the win, although we suffered a lot," added Villa. "We deserved to win, though, so I believe the result is fair.
"Individually they have two excellent central defenders, but luckily we were able to take one of our chances.
"My aim is to keep scoring like this, especially in the big matches, so we can advance through the tournament.
"I thank the fans for their support. We have kept on improving as a side after the loss to Switzerland in the opening match."