The south coast derby is touted as one of the biggest rivalries in English football and that certainly appeared the case ahead of kick-off.
Videos show both sets of fans walking to Fratton Park with heavy police escort.
When the match eventually did kick-off, the Premier League side showed their class.
A Danny Ings brace put the away side 2-0 up before half-time.
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That didn’t quieten down the home fans who were in fine voice throughout.
But Ralph Hasenhuttl’s side made it emphatic towards the end of the match.
Cedric Soares made it 3-0 before Nathan Redmond put the icing on top of the cake with five minutes left.
League One Pompey probably didn’t appreciate being outclassed by their biggest rivals live on Sky Sports.
However, that’s no excuse for the disgusting behaviour of one Portsmouth fan after the match.
A video emerged of one man shockingly punching a police horse in the street.
But the thug got what he deserved.
He was chased down the street by the horse before running into a large group of police officers.
He was then floored and deservedly reprimanded.
There’s simply no excuse for that kind of behaviour.
After the game, Hasenhuttl admitted he was pleased with the victory - more for the fans than anything else.
"This is more than only reaching the next round," said Hasenhuttl.
"This is about reaching the hearts of the fans. I am very happy for them.
"I knew it was massive game for them and I think we really didn't start well in this game, but the players knew they had to fight for every inch."News Now - Sport News