Ole has to take most of the criticism for that performance. Why not continue with Romero for the cup games? Why change to 3 at the back when we haven't really played it for months? Why rest Pogba instead of Fernandes, when he was clearly the one who has looked knackered in the last games? Why start James when he's showed little or no promise in recent games, rather than Ighalo for example? Baffling decisions.
As soon as the formation reverted to 4-2-3-1 and then Pogba came on in the second half we looked much more competitive, and could at least keep possession and put together some attacking moves, though Maguire still looked understandably off his best after the clash of heads. Another CB or even two will be essential in the summer.
I reckon if we'd played Romero, kept with 4 at the back and just swapped a few of the more tired players (Fernandes, Greenwood), we'd have won that, as Chelsea were not particularly impressive in the absence of our (or rather DDG's) mistakes.