Form the performances of the clubs in the group D of this season's UEFA Champions League competition so far, I think Inter Milan are the favourites to win the group. They've been exceptional this season and if they continue their great form in the Italian Serie A, they might be playing in the final of the competition once again.
Benfica I think also stands a chance to progress to the knockout stages. Real Sociedad and Salzburg didn't come to waste their time in the competition so they also will do their best to qualify
For group D it seems that many people will also make Inter Milan the favorite in this group phase and of the 4 teams in group D only Inter Milan has the most chance of leading the group and qualifying for the last 16 but when you look at Inter Milan at Setie A it is also very likely that Inter Milan can play well until the final round like last season Champions League.
In the first match of this group phase Inter Milan will meet Real Sociedad and there will be a difficult challenge for Inter Milan to beat Real Sociedad because they are a team that is quite strong in La Liga and often provide unexpected surprises in every match when against same team strong.
But still for both of them Inter Milan is still the favorite.