Lookman struck in the comfortable victory on Wednesday night.
He told Sky Italia afterwards: "Yes, tonight's match was crucial for us. We had to win, especially after the draw against Arsenal. It was important to confirm our level with the three points.
"I think we played a great team performance, even if I personally don't think I played my best match. But the objective was the three points, and that's what counts. I'm happy with the goal and the result.
"It's true, in Europe we are showing excellent levels of play. In the league we have had some declines, but we are growing, and we are becoming stronger with increasingly convincing performances. I believe that in Serie A we can also achieve important results, as we demonstrated tonight in the Champions League.
"Every game is important, both in the league and in Europe. We want to progress in both competitions. As I said, we are focused on improving game after game. Serie A is as important as the Champions League, and the goal is to bring the same winning mentality to every game."