Man United finished top of Group A after beating CSKA Moscow in their last fixture of the group. However, it could have been better if they had allowed Basel take the top spot as they face being drawn with a difficult opposition in the round of 16.
After UEFA confirmed teams from both countries cannot meet in the next round, Chelsea have been exempted from being a possible opponent. However, Bayern Munich, Juventus and Real Madrid are all confirmed possibilities for United. With Liverpool topping Group E then United can also face Sevilla.
Other possibilities are FC Porto from Group G or Shakhtar Donetsk from Group F and FC Porto from Group G.