Athletic meet Barca on Saturday night.
"I expect a very difficult game. We're talking about an opponent who, in terms of potential and quality, are candidates to win LaLiga," Valverde said at his pre-match press conference.
"We'll go there and play with the aim of winning. It's a stadium we don't do very well at. But every time we play there we have a new opportunity to win.
"We always want to win, no matter the opponent. It's a team we haven't beaten away for a long time.
"We're not the only ones. We're talking about a team that is always in the running to win the title. It's difficult to pick up points there, but this is an opportunity to do so and we're looking forward to it."
Valverde added: "We weren't as good as we would've liked against Getafe. We tried, but the opponent was very strong in the duels and disputes, as you have to be, and they didn't let us play our game.
"Now we have a tough week ahead. It's a complicated start to the season, which has been made more difficult by not winning the first game. That's why we need points. We have to play these three games with the utmost enthusiasm and commitment."