The winger wrote “F***ing disgrace, I have no words” alongside a photograph of himself on the pitch after Tuesday’s Champions League loss. It remains unclear whether his message was directed at Manchester United’s performance, the club’s leadership or the wider situation surrounding the team.
Diallo came off the bench to play the final 25 minutes at the Metropolitano, where United suffered another damaging result under head coach Michael Carrick.
The visitors conceded inside the opening minute when Pablo Barrios scored for Atlético. United remained in contention for much of the second half, but Leny Yoro’s dismissal left them with ten men before Ademola Lookman struck the decisive second goal.
The defeat was followed by a separate controversy involving Lisandro Martínez, who publicly criticised the club’s hierarchy and called for greater investment in the squad. The defender questioned whether the club’s recruitment strategy had provided Carrick with enough quality and depth to compete against Europe’s leading sides.
Martínez said he expected more from director of football Jason Wilcox and argued that the responsibility for United’s difficulties should not rest solely with the manager and players.
“I expect more. I’m not going to close my mouth,” the Argentine said, adding that the club needed greater ambition and should be speaking openly about winning the Premier League and Champions League.
The defender also pointed to the demands of competing across multiple competitions, arguing that United did not have the strongest squad compared with other leading clubs.
Diallo’s post came against that backdrop, although there is no evidence establishing that his message was a direct response to Martínez’s interview.
The winger’s frustration will nevertheless add to concerns about the mood around Old Trafford following another poor European performance. United have struggled to turn their attacking spells into goals and have repeatedly been punished for defensive errors.
Carrick now faces pressure to produce an immediate improvement, with a Premier League trip to Leeds United next on the schedule.
The public reactions from members of the squad have intensified scrutiny of the club, but the precise target of Diallo’s message remains unknown. United’s players must now respond on the pitch if they are to ease the growing pressure surrounding the team.