Liverpool manager Jurgen Klopp called out Leeds for placing a Champions League T-shirt bearing the message "earn it" inside the Reds' dressing room ahead of the two clubs' 1-1 Premier League draw on Monday.
For their pregame warm-ups, Leeds players took the pitch at Elland Road wearing the shirts, which also displayed the message "Football is for the fans" on the back.
Liverpool confirmed on Sunday they were one of six Premier League clubs to become part of a breakaway Super League. And despite the league's plans to have 15 permanent members benefit from the potentially lucrative 20-team enterprise, Klopp said his team did not need to be reminded how qualification for Europe's top competition works.
"I saw there are warm-up shirts, which we will not wear. We cannot, but if someone thinks they have to remind us that we have to earn it to play in the Champions League, it's a joke. A real joke!" Klopp said.
"And they put [the shirt] in our dressing room. If it was a Leeds idea, thank you very much. Nobody has to remind us. Maybe they should remind themselves."
The German, who has spoken out in the past against a European Super League, told Sky Sports television that his opinion had not changed since 2019 when he said he hoped it never happened.
"I heard first-hand about it yesterday," Klopp said. "We got some information, not a lot to be honest. Most of the things you can read in newspapers or wherever.
"It's a tough one. People are not happy with that, I can understand that. But I cannot say a lot more about it because we were not involved in any processes, not the players, not me. We didn't know about it."
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While no fans are allowed into Elland Road, a large banner draped across the seats read: "Earn It on the Pitch. Football Is For the Fans."
Some fans gathered outside Elland Road to voice their anger, with one banner reading: "RIP LFC. Thanks for the Memories."
A philosophical Marcelo Bielsa called the announcement of the Super League unsurprising.
"It doesn't surprise me. The most powerful teams have achieved their power from the competition against the rest of the teams. Now it looks like they don't need us anymore to earn more money and the method they use is to discard the ones that no longer serve their objectives," he said before the match.
"This didn't happen from one day to the next. A lot of regulations and rules that limit inequality have been made more flexible and granted this situation to become inevitable.
"There are two sides about this. The most powerful teams are what they are because of what they produce and the attention they provoke. But the rest of the teams are indispensable. The core of competition is helping the weak to develop, not the excess growth of the strong. The logic that prevails in the world, and football is not out of it, is that the rich are richer at the cost of the weak being poorer."
The game itself was crucial for Liverpool's hopes of qualifying for next season's Champions League. They now sit in sixth place but a victory would have seen them leapfrog into fourth spot, above Chelsea and West Ham United.
Leeds' Twitter account poked fun at Liverpool after the result.
"#LUFC hold Super League side Merseyside Reds to a 1-1 draw after late Llorente equaliser," the tweet said.
FULL TIME: #LUFC hold Super League side Merseyside Reds to a 1-1 draw after late Llorente equaliser— Leeds United (@LUFC) April 19, 2021
Speaking after the game, Klopp reiterated he and his players had nothing to do with the Super League plans.
"I don't think it is right. They put them in our dressing room, I don't think we deserved that. I don't like the way a lot of people are talking about Liverpool.
"This is a fantastic football club. In this specific moment we can't blame the team for that. I take the criticism for everything, but this we have nothing to do with.
"Now people write articles about what they should do with it. People are shouting at us. We have to be careful because we are people as well. We have to be careful. I understand all the talk and I don't like it as well."
Liverpool midfielder James Milner added to BBC Sport: "I can only give my personal opinion and I don't like it one bit and hopefully it doesn't happen.
"It [the current system] has worked well for a long time. What has made it special what we have done over the last few years is we have earned the right to win the Champions League and earned the right to win the Premier League. The product we have currently is very good.
"It is difficult. Coming into the game today Leeds fans were making their feelings shown. As players we don't really have a say, so it feels a bit unjust. All we can do is try and win football matches."
Liverpool fan group Spion Kop 1906 announced that they and other groups involved in decorating Anfield's iconic Kop during the coronavirus pandemic will remove their flags as a protest against the club's involvement in the Super League.
"We, along with other groups involved in flags, will be removing our flags from The Kop," the group wrote on Twitter on Monday.
"We feel we can no longer give our support to a club which puts financial greed above integrity of the game."
American-owned Liverpool are joined by Manchester United, Manchester City, Chelsea, Arsenal and Tottenham Hotspur as founders of the Super League, along with AC Milan, Inter Milan, Juventus, Real Madrid, Barcelona and Atletico Madrid.
Supporters' clubs of all six Premier League clubs have come out in opposition to the Super League, which would be a direct rival to UEFA's Champions League -- the competition Liverpool won for the sixth time in 2019.
Information from Reuters was used in this report.