Milan can't suddenly start being a great team in UCL just because they are losing in the league. I mean they are not doing that great right now and they won't do anything good in UCL neither, that is not going to happen, that is going to be a problem for them.
Doesn't mean they can't beat Spurs, there is a good chance that they could beat Spurs and that could happen, but that doesn't change the fact that we will see them do even better afterwards, the best they can do will be beating Spurs, after that, unless they get a very very lucky draw from a much smaller team, they are going to lose, and there is a big possibility that they will lose to Spurs as well.
Spurs are a tough opponent, but also equal with Milan. unfortunately, currently Milan is in a bad situation. Milan's performance will be doubted when going through the match against Tottenham, even though in the first leg Milan will play the match as the home team. but with the situation that occurred in the domestic league, plus several core players who were injured. Naturally, if Milan is not the favorite in the match later. but at least Pioli has said that he and his team will prepare as best they can. So, Milan's only advantage in such an unstable condition is playing at home in the first leg. for sure, Pioli's men's squad will have to take advantage of the momentum later.
Conversely, the Spurs situation is also not in its best form. in fact, they slipped several times in their domestic league. even so, it seems Spurs are better prepared when facing Milan at the San Siro later. at least, Conte will take advantage of his very familiar experience with Serie A teams. So, let's just wait because this match will start soon in the next few weeks.