Guardiola signed a new two-year contract with City on Thursday.
Haaland, asked about their four consecutive defeats, told Sky Sports: "We've lost four in a row and that's not normal at a club like this. It hurts, of course. The motivation is greater than ever to play on Saturday, win the game and get back on track.
"I think it's important to just let go. It's the hardest thing, even in life, to let things go and be sad and all that. But we have to focus on the next one, look at how many games there are... I haven't thought about the last 4 games, in fact I went to the national team and won two. It's about starting again, living in the present and looking to the future. It's not that serious, it's not like we're relegated. We're second and there are a lot of games to play.
On Guardiola, he continued: "He is calm. We just have to do our best because he demands a lot. He asks us to be at our best in every training session, in every match and that's what we have to do. Let's try to win the next one straight away. Let's focus on today's training, tomorrow's training and then the match. Pep has my full trust. And if he tells me something, it's better for me to do it because in the end he knows what's best. So I'm sure he'll find solutions now too.
"He is exactly what I expected. He is the best manager in the world and I think we all know that. And he is probably the best that has ever existed on earth. I expected a lot of things from him and he gave me his best every single second. I am super happy and you can see it when I play. He always wants perfection but perfection does not exist. What matters is winning trophies."
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