I think Walter (he has stated himself that boyd can't play the lone striker role) has to take the blame for Boyd last night - everyone knows Boyd is limited to what he can do and was never going to do well playing up there on his own (although i don't think he done any worse than what we've seen from this champions league campaign) - he needs a partner up there to help him, it's as simple as that.
To be honest though whoever played up top on there own last night would have struggled because the midfield are so slow to support it's unbelivable how slow our build up play is