Sheffield United took a mighty battering at home to Eddie Howe's side after they were thrashed 8-0.
And watching on from one of the hospitality boxes was Newcastle legend Shearer, who was in attendance at Bramall Lane with some friends.
But as he celebrated the goals flying in for the Magpies, some home fans around him became disgruntled.
It led to some fans hurling abuse at the Premier League icon and Shearer has since hit back after joking about the extravagant scoreline towards them.
He told The Rest Is Football Podcast: "Unbelievable. Eight different scorers, brilliant atmosphere, it was great to be with my pals as a fan for once.
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"I was getting a bit of grief because we were in a pal's box in the Sheffield United fans when I was stood up clapping when we scored.
"I don't know what it was but the fans kept doing that [putting two fingers up] to me.
"I thought they were saying it was 2-2, but I kept saying it was 8-0 you f****** idiots. I have to say the Sheffield United fans were amazing.
"If that was me and my team, I'd have left long before the final whistle, but there were thousands of fans that stayed.
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"It was a tough afternoon for the Sheffield United fans. That today was magnificent from every player.
"Sheffield United were really poor. After two or three minutes I said to one of my friends 'if we don't win this, it's going to be a long season for us'.
"But they dominated and it could have been, maybe should have been, more."
It was the first time in Premier League history that such a scoreline saw eight different goalscorers.
Sean Longstaff, Dan Burn, Sven Botman, Callum Wilson, Anthony Gordon, Miguel Almiron, Bruno Guimaraes and Alexander Isak all managed to net against the Blades.
The result gives Eddie Howe some breathing room after a difficult start to the season, though he denied it was a complete performance.
He said: "It was very good. I don't know whether it was the complete performance.
"We are always looking to find things to improve. It's a really tough place to come, especially off the back of a European week for us, so I'm delighted with the players.
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"If we didn't turn up in the best condition Sheffield United would have beaten us.
"We started really well and got the goal early. That settled us down and we played some really good football after that. It shows you that the players were very motivated for the game. They were hungry for goals and for success.