They are one of the favorites for sure.
Lazio and Athletic Bilbao are two of the strongest teams in the league. Manchester United and Tottenham didn't perform like them. In the end it's still in group stage so don't come to conclusions easily. As long as they advance to quarter final there will be no problem.
All still have a chance and maybe both are one of the favorites because their performance in the competition is still on the right track, but the level of consistency will be a test for everyone because the group stage is only the initial stage for the team before advancing further to the final round. Manchester United, Tottenham are also strong candidates but in terms of team performance, both have declined because they are not consistent. Going through the group stage might give a little picture of how the competition in the European league can be much more interesting for the teams that make it through.