Roma beat the Dutch side on their way to Budapest, where they lost to Sevilla on penalties, ending Mourinho's run of five wins from five in European finals.
It's fair to say that the former Chelsea manager didn't take the defeat well, raging at referee Anthony Taylor, which has earned him a UEFA charge.
And his mood won't be helped if he logs onto TikTok, where Feyenoord have mocked his comments after their last meeting.
Tensions were already high due to Roma beating the Rotterdam side in the Europa Conference League final the previous season, and they were raised when manager Arne Slot appeared to criticise Mourinho's football, saying he 'prefers to watch Napoli or Manchester City'.
Roma ended up knocking Feyenoord out of this season's Europa League, scoring three unanswered goals in extra time after both legs had ended 1-1.
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And in the tunnel, a heated Mourinho was filmed shouting: "You should watch us! Not Napoli!" at Slot as the two headed to their respective dressing rooms.
However, Feyenoord have now hit back, as Roma's defeat means they won't be in the Champions League next term, unlike Feyenoord who won the Eredivisie.
Posting Mourinho's tunnel outburst at Slot, Feyenoord's TikTok video then shows Roma legend Francesco Totti pulling the Dutch side's name out at the Champions League draw, and features the competition's anthem and the caption: "No, you should watch us!"
The music then cuts to the Europa League anthem, and shows Mourinho wiping tears from his face at full-time in Budapest.
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They even captioned the clip, 'See you next seas... oh'.
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