Navas & Fernando subs made a big difference but so did GladBach's energy levels dropping off a cliff
I think this can be a key part of our tactical substitutions in the second half.
1. Sub Yaya for Fernando if we are ahead and to keep it more tight in the middle. Need to preserve Yaya from now on.
2. Sub either of Silva or Debruyne for Navas when the opposition legs are tired.