Chelsea sparked a backlash on social media users after their players failed to wear black armbands during the first-half of the FA Cup final.
The oversight, said to have been because they simply forgot, was rectified as they took the pitch for the second 45 minutes.
However, their error was compounded when Victor Moses threw his armband on the ground in frustration after he was sent off.
Arsenal and Blues stars had observed an impeccable minute’s silence before kick-off in honour of the victims of the Manchester Arena attack.
But supporters at home spotted Antonio Conte’s men not sporting tributes on their arms – unlike their north London rivals.
The reason for the lack of armbands was apparently down to Blues players forgetting, having been distracted by a discussion about wearing training tops.
“Good to see Arsenal wearing black armbands as a mark of respect. Shame Chelsea couldn’t do the same,” tweeted Graham.
Kim questioned: “How come Chelsea players aren’t wearing black armbands?”
Hannah fumed: “Can’t believe the Chelsea players aren’t wearing black armbands. How disrespectful.”
Wembley fell silence to pay tribute to the 22 concert goers who were killed by a suicide bomber on Monday.
Earlier in the week, Chelsea confirmed they would be wearing armbands.
A statement said: A Chelsea statement read: “As a mark of respect, our players will wear black armbands at the FA Cup Final against Arsenal on Saturday.
“Chelsea Football Club will also make a donation to a fund supporting the victims of this horrific attack.”
The Blues told BBC presenter Dan Walker that: “Chelsea players forgot to put the armbands on. It’s completely accidental. They will be on for the 2nd half.”
116 other fans were injured as adults and children streamed out of an Ariana Grande gig in the north west city.
The Gunners also sported black armbands, fans held up “I heart MCR” posters and Prince William lay flowers on the touchline.
Security at the national stadium in London was stepped up for the final despite the terror threat was reduced from critical to severe.
Gunners and Blues fans had been warned to arrive at Wembley early for increased security checks – with 90,000 supporters descending on north-west London.
Heavy police presence was seen around the area – with the Metropolitan Police previously confirming extra armed officers will be deployed with a full review of the security and policing operations under way.
Earlier in the week, Manchester United paid their own respects ahead of their Europa League success over Ajax.
Tens of banners were placed on display to honour their hometown friends while United stars stood silent both in training before the game and ahead of kick-off.