Think it is fatigue, but also poor formation and poor player management leading up to this. Can't blame him for one game but it hurts that every game is a must win, and those last minute second half strong finishes (as much as we did finish strongly) your luck can run out, like it did last night. Although last night wasn't just luck against us, its poor management.
So we start with unfamiliar tactics of 5 at the back and a guy that's just come back from injury (when, as bad as lindelof, de gea, maguire has been as a combo, at least it is familiar). You also put two left backs in to play on top of each other, and expose wan bissaka. Obviously AWB was told to make the game narrower, but greenwood was too green to be able to help (not enough experience, no blame on him) because otherwise they'll run through the middle, and angelino had all the space in the world.
About the left side, we packed that side and didn't know how to use it, as much as they offer different things in terms of final third of the field, they used up the same space. With Rashford and Bruno also often tending to that side (at least in the first half) you had 4 on the left, plus maguire covering, and matic. So 4 people and matic trying to occupy the same spaces, there's nowhere to run, and 2/5 are slow passers in matic and shaw, and the other three are short sharp one-two passers of the ball. You didn't need many defenders covering those 5, RBL used 3 with high energy pressing, and the managed to mess up or get in each other's way all the time.
So just too congested leaving first mctominay to have to patrol huge areas along with AWB, and the two of them having to cover 3+1, or 3+2 when the second or third midfielders joined, or swung the ball wide to the flanks.
Back to Thursday night football, and it looks more competitive than ever. From a player point of view I would have preferred not playing the Thursday nights rather. It is what i say every year that we're in europa, but more so this year.