Manchester United legend Denis Irwin says they cannot afford to lose at Champions League opponents Real Sociedad.
Irwin wrote in the Sunday World: "The reason for that is simple. This season, with their eyes on a long run in the competition, it will not be enough for United to qualify from their group, they must win it! In the last 16, teams from the same country cannot meet, nor can group winners - and look who the other potential group winners are right now.
"The three Spanish giants, Barcelona, Real Madrid and Atletico Madrid, are leading their groups. As are the German powerhouses Bayern Munich and Borussia Dortmund.
"Add in PSG, with Zlatan Ibrahimovic in brilliant form, who are topping their section and frankly it is a line-up you would want to avoid."
