The Swede struck a first Premier League goal for Liverpool in Saturday's 3-1 win.
Isak told liverpoolfc.com: "I felt like that shot was not going in so I kind of intercepted it and it became a good touch. Then I managed to put it into the back of the net.
"I’ve been battling getting back to full fitness and obviously scoring a goal is probably the best way to finding your form again. Obviously I’m really happy."
On goalkeeper Freddie Woodman's performance, he also said: "I think he did absolutely brilliantly. It’s never easy to come in, especially in a position like him where you have to be ready but it’s not often you get the chance.
"It’s really big from him to be able to put on a performance like this. I think he deserved a clean sheet. But a really big performance from him."