The 29-year-old has heaped praise on the Catalan giants, but is remaining optimistic as he prepares to face the Liga leaders at San Sebastian
The Basque outfit will welcome Tito Vilanova's side to Anoeta on Saturday and the 29-year-old was quick to lavish praise on the current Liga leaders.
“They are a machine and the figures speak for themselves. They are verging on perfection, I take my hat off to them,” Prieto told Barca TV.
“We are excited to be welcoming Barça, they’re the best team in the world and play the best football.
“Messi is the best player in the world. I hope he doesn’t play on Saturday because 91 goals is a number from another galaxy.
However, the goalscoring midfielder is still retaining some hope that his team may get something from the game.
“Anoeta is a place where we have got a lot of points and where we have some very passionate fans. In the last two years we have always made things very difficult for Barça, with one win and a draw," he added.
“We will stay faithful to our own style, but we’ll probably see less of the ball, because it’s impossible to get it off them.”