With the exception of the opening 30 minutes of last Saturday's 3-0 win over Southampton at St Mary's, Manchester United's defence has barely been tested since the September international break.
After back-to-back defeats at the hands of Brighton & Hove Albion and Liverpool prior to the pause, in which United conceded five goals, there was an expectation for them to improve defensively following the restart.
On paper, clashes with Southampton and Barnsley looked like ideal opportunities to do so - and so it proved. United scored 10 goals over the course of 180 minutes without reply.
Although United were expected to beat Barnsley without too many difficulties in Tuesday night's Carabao Cup third round tie at Old Trafford, few probably anticipated Erik ten Hag's troops would make mincemeat of the League One side.