Inaki Williams and Dani Vivian scored for the visitors on Thursday night.
Valverde later said: "It was a very tight game between teams that were trying to get through in different ways. The pitch was very wet, but it was good. We had more chances than we perhaps managed. We lacked something to define the game because we had the game.
"They created a double chance, but we always had a chance to get through. In the second half, they broke the deadlock with our goal and they became more motivated. It was difficult.
"In the first four games we didn't get what we wanted and now we've reached an important week for us in the league. It's a reinforcement for what's coming and we want to finish well this week against Celta . What no team wants is to be in a hurry to win. We are humble and we recognise that every game is a fight and many times a game depends on a rebound."
On the importance of Vivian, he continued: "Vivian is a sure thing. The question is the level of concentration he has for 90 minutes , which is not easy. He doesn't concede anything and look at this time he had (Sebastien) Haller in front of him. For us he is a fundamental bastion and he also has the reward of going to the national team."
On Nico Williams' injury, Valverde added: "He has a sprained ankle. We'll see if he can recover for Sunday, which will be difficult, and we'll see if he's ready for next week."