A subject to think about

[Tactician]

I was in the same situation a couple of seasons ago, the same team which was in my Legue (I won the Legue and him personnaly in League games) also played against me in CL, but it was my mistake since I underestimate him after Legue games.

Underestimated or not, you would still have lost if the game already gave a lot of hidden advantages to the other team for that particular match. In some cases, nothing much can be done as a manager to change the final outcome, that is win or loss. If you have the quality advantage (but not to the extremes) and if you use superior tactics, you might earn a draw, but you will still lose on penalties. You will even notice how the game set things up and make things happen so that the 'already decided' outcome in terms of win or loss is respected. If you keep on observing for a few seasons, you might even see similarities and trends concerning such things (which means that these have been programmed to occur as such; there are no coincidences). So far, the only way to override this is to have quality advantages as high as +80% and above compared to the quality of the opposing team, where the significant advantages given by the game to this opposing team won't be enough to make you lose. In other words, this is the only guarantee to win, but it is expensive and hence not worth it, especially for a game like this.