For a start: How can a side who have looked so disjointed over recent months provide such a fluent and determined response to going 2-0 down at home of the Premier League champions elect?
And what on earth is Chelsea's best lineup and formation?
If we continue to berate Rafael Benitez for some of his tactics and substitutions which are perceived to have cost the team games and points, then do we need to give the Spaniard credit for instigating changes at Old Trafford? And why can't some of Chelsea's star turns put in more than one positive shift in a row?
For example, both Eden Hazard and John Obi Mikel were arguably the most underwhelming performers out of the lot during the Blues 1-0 loss away to Steaua Bucharest last Thursday, but their arrival on Sunday marked a sea shift in the game with Chelsea grabbing a foothold.
On top of that, neither Demba Ba or Fernando Torres have done enough to make the striking slot their own, and Benitez still appears to be pulling names out of a hat to make up the back four.
All of which means that nobody really knows what makes the best starting XI for Chelsea. Even if there was a conclusive answer, would that team end up doing the business? Some of Benitez's decisions make it easy for him to be criticised, but in his defence there are few players consistently easing the burden.
For me, Oscar drifts in and out too much, and although Victor Moses has been a persistent threat out wide when he plays, the Nigerian has been patchy in his past few performances.
Frank Lampard's spell of great form either side of Christmas has worn off with the vice-skipper playing well below par of late, and that problem is exacerbated by the ultimate Jekyll and Hyde––Ramires.
There's only Juan Mata you can hang your hat on, and the conundrum for Benitez is that he needs to rotate a squad who are largely unpredictable and inconsistent.
So what will he do over the next few days as Chelsea battle on two fronts to prolong their Europa League challenge whilst also attempting to seal a top-four finish?
First up it's Steaua Bucharest at home on Thursday night, with the European champions needing to overturn a 1-0 first leg deficit to progress to the quarterfinals.
Then on Sunday it's back to Stamford Bridge for the visit of West Ham with another vital three league points up for grabs in the three-way playoff with Arsenal and Tottenham for third and fourth place in the Premier League.
At this stage of the season, and with plenty of bodies fit––if not exclusively on form––there is no need to prioritise either competition. Yet that does not mean that alterations don't need to be made considering the opposition. To throw a Cheltenham festival analogy in, it's very much horses for courses.
With that then in mind, here is my starting XI to get past Steaua:
Cech, Ivanovic, David Luiz, Terry, Cole, Ramires, Mikel, Mata, Moses, Hazard, Torres.
So let me explain.
I've gone for Branislav Ivanovic at right-back to give more defensive cover than Cesar Azpilicueta but left David Luiz in to give us a ball-playing element from the back. On a night when you need a big result and a strong performance at home I've reinstated John Terry, with Gary Cahill's recent form doing little to dissuade me otherwise.
Frank Lampard has been well off the boil of late, and although I'm not a fan of playing Ramires at home, he and Mikel dovetailed well enough at Old Trafford to warrant another go. Lampard is an ideal substitute to bring off the bench when in need of a goal.
Ahead of those, Juan Mata picks himself. Eden Hazard should be buoyed by his strike against United and his rocket last time out at home in the competition versus Sparta Prague.
Completing the trio was a more taxing ask, but I've gone for the pace and power of Victor Moses over the subtlety of Oscar.
That's a controversial call given the baby faced Brazilian is our top scorer in European competition, but I think the best way to beat Bucharest is to ravish them from the off at a tempo they cannot deal with, and the width Moses gives will provide a natural outlet to tear into the Romanians.
I've felt Chelsea have looked most balanced with Moses operating wide as part of the attacking midfield three, and getting bogged down in a tight midfield battle is not the way to go when needing two goals to go through.
Up front it was an enforced decision to pick Fernando Torres with Demba Ba suspended, but the under-fire Spaniard has seemed more lively––albeit goalless––in recent weeks, and with the right support and a decent early tempo, there is still always the possibility of a goal.
So that's how I would line up, and I'd be confident that side has the correct personnel, shape and balance to get past a tricky proposition.
Dominating the game from the off is key, and pinning the visitors back will give Chelsea the foothold to grasp the game for long periods.
There would also be plenty of variation on the bench for any scenario, and there are no excuses why Chelsea should fall at this stage of a competition they have a strong chance of winning.
I suspect there will be many different variations coming from the public, so hit me up with how you'd go against Steaua.
Stick your comments down below and let me know how and why you would stray from what I've picked.
For more Chelsea related ramblings, feel free to follow me on Twitter @bainesyDiego10