It meant a fourth consecutive defeat in all competitions for Chelsea.
Hato said: "We had a few difficult games in a row so maybe it's a good time now (to have the international break). Everyone has the time for themself to think about how we are going to do it after the break. But I still have a lot of belief in this squad and I think we will reach what we want to reach (this season).
"It's hard to say what it is, but with how painful it is, we have to take this one and look forward. We now have an international break, so everyone has time to think about the next games.
"We are still in the FA Cup, we can still reach what we want in terms of the top four (in the Premier League), so we have to look forward."
Asked if the Blues lacked confidence when going 1-0 down, Hato replied: "No, I don't think it's a confidence issue because we went 1-0 down but we still created chances, we still had control of the game. So I don't think that was the issue, but after they made it 2-0 and then 3-0, it's tough to come back.
"Maybe in the beginning, the first 15 minutes, they were pressing well. But after that we had control of the game, we created chances and they were spending most of the time in the game very deep in their own half. But it was hard, it was difficult to score, and it was just not enough."
He added: "It was not enough from us. I think we tried, but today was not enough."