Newcastle United fans protesting against owner Mike Ashley displayed a giant banner in the Gallowgate End of St James' Park before Wednesday's 1-1 draw against Burnley.
The banner, consisting of eight sections displayed on four levels, used a quote from former Newcastle manager Kevin Keegan.
Although it did not mention Ashley by name, its 62-word message targeted the billionaire, who has put the club up for sale but has yet to conclude any deal.
It read: "Don't ever give up on your club. Keep supporting it, it's your club and trust me, one day you will get your club back and it will be everything you wanted it to be.
"Newcastle United is bigger than anyone. It hurts, I know, but just keep going. He is only one man we are a city, a whole population. Trust me."
Reports suggested the club had been unaware of the existence of the banner before it was displayed at 7.35 p.m, 10 minutes before the match kicked off.
Newcastle fans have recently voiced anger at the club's hierarchy for failing to back manager Rafa Benitez in the transfer market following last season's promotion back to the Premier League.