United's cross-town rivals Manchester City could not resist the opportunity to take their own, personal potshot at Webb on his way out of the Premier League door, as he leaves active refereeing service to take up a post as technical director of the Professional Game Match Officials Limited.
The game being referred to is the 2006 FA Cup quarter-final between Stuart Pearce's City and Alan Pardew's West Ham at Eastlands.
The Hammers prevailed 2-1 thanks to two Dean Ashton strikes n their way to an eventual meeting with Liverpool at Wembley - but not before Manchester City had been reduced to ten men following the dismissal of Sun Jihai for a swinging arm.
They felt the decision to be unfair at the time - and more than eight years on, Webb's departure has given them an opportunity to air the festering wound in public once again.
Of course, United's "noisy neighbours" were by no means the only ones taking aim at Webb on an afternoon when Twitter revealed its claws.
Nary an opportunity was missed to remind the world of social media of Webb's supposed bias towards the red half of Manchester.
So Howard Webb announces retirement so that he can spend more time with the family... pic.twitter.com/LIvbAjNxlCLADexperience (@LADexperience) August 6, 2014
Feel so sorry for these man Utd fans after they have just heard the news about Howard Webb retiring pic.twitter.com/e9XthPPsShScott Murray (@Scotty_Murray) August 6, 2014