The 58-year-old was apprehended by the authorities after a still from the TV footage of the game was circulated on Twitter, appearing to show him making a racist gesture in the stands.
A Merseyside Police spokeswoman said: "A 58-year-old man from North Wales who was arrested on suspicion of a racially aggravated public order offence yesterday following the Liverpool and Manchester United match has been released on police bail pending further inquiries."
Saturday’s match was the first meeting between the bitter rivals since Liverpool striker Luis Suarez was handed an eight-match ban for racially abusing United defender Patrice Evra, and the Frenchman was subjected to booing from the Anfield crowd throughout.
Before the clash, the stadium announcer warned supporters that racist or homophobic behaviour would not be tolerated, and it is believed any individual found guilty of such offences would face a lifetime ban from the club.
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