A sustained, aggressive intensity rarely seen in the English game at the highest level at Stamford Bridge last night would test even Pierluigi Collina in his prime, but beyond penalty calls and missed handballs there was clearly something amiss with Michael Oliver's attempt to manage the game effectively.
Oliver can be excused for missing Diego Costa's stamp on Emre Can, an incident which happened in a flash and was arguably expertly timed by a forward well versed in the kind of dark arts which make him such a nightmare for teams facing Chelsea to contain.
You can even make a case for the 29-year-old not giving what looked like a definite penalty after Costa tangled with Martin Skrtel, again a moment that came and went in a flash in a free-flowing match played at a breathless pace.
What was going through his mind?
What shouldn't be excused is his quite baffling decision to shake the hand of Branislav Ivanovic before handing the Serbian stalwart a yellow on the card.
On the surface that moves looks innocuous enough, but it just served to make the baby-faced official look like he was trying too hard to regain control of a match that threatened to boil over right from the word go.
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Move sign the young official was overwhelmed?
A wonderfully entertaining cup tie needed an authoritative, experienced figure to take the reigns and make the right decisions under pressure, something Oliver failed clearly to do.
Chelsea manager Jose Mourinho will feel aggrieved at the penalty call that didn't go his way, plus even more alarmingly the fact Lucas Leiva and Jordan Henderson both stayed on the pitch despite indiscretions not difficult to spot while already on a yellow card.
Mourinho has been more critical than most of officials and recent weeks and quite frankly he has a point, based on Oliver's performance and many similarly confusing displays from his top-level contemporaries over the first five months of the campaign.