Isak scored his second goal of the season, converting Florian Wirtz's cross on the hour to cancel out Dan Ndoye's opener, before Victor Munoz's late strike completed the comeback following Morgan Gibbs-White's penalty for Nottingham Forest.
It was the second successive weekend Liverpool have needed to fight back from behind, having also drawn 2-2 at Newcastle.
"I think there's no problem in fighting spirit and never giving up. I think we showed that last week as well," Isak said. "Obviously we started the game pretty bad today as well.
"When we gained momentum by scoring a goal, that's where we need to be better, I think, because again today we conceded quite quickly after that.
"But from the position we were in, it's always good to get something out of the game."
The Sweden international is still adjusting to life under new head coach Andoni Iraola.
"It's been good. There's always time to get used to a new playing style and a new manager. But we are really working hard to try to play the game he wants us to play and I think when we start doing that better, I have no doubt that the results will come."
Isak has now scored in back-to-back matches and said he feels an added weight of expectation as Liverpool's central striker this season.
"Yeah, of course. That's the job ultimately as a striker. Obviously I'm very happy to score the first one and hopefully it just keeps coming." Asked whether he sets personal targets over a campaign, he said: "Not really. I think every striker wants to score in every game he plays. Obviously that's difficult, but take each game at a time."
Reflecting on scoring in front of the Kop for the first time this season, Isak added: "It was amazing. I think our fans were amazing. Really happy to be back here at home and I can't wait to be back here again."