Klopp voiced strong concerns about player welfare and slammed FIFA for expanding the tournament. The competition has grown to 32 teams and is now scheduled to be held every four years. The inaugural edition under this format is currently taking place in the United States.
"The Club World Cup is the worst idea ever implemented in football in this regard," Klopp told Welt.
"People who have never had anything to do with day-to-day business or who no longer have anything to do with it come up with something."
Criticism has mounted around several aspects of the tournament, including poor attendances, the quality of pitches, and extreme weather conditions affecting match quality and player safety.
"Listen, I fought a lot with Jurgen many, many times. I know where his idea comes from," Guardiola said at a press conference in Orlando.
"We fought a lot in England, and also when we went to the UEFA meetings, and especially when we discussed the Premier League calendar, and how to add more quality to it. We discussed giving the managers and players more rest, because that's how you add more quality. So his comments didn't surprise me a lot.
"I understand him. I respect him. I've had an incredible relationship with Jurgen for many years as rivals. Now he's stepped back from that position as a manager and I understand his argument, because I would defend his argument as well."
Manchester City, managed by Guardiola, are due to face Saudi Arabian side Al-Hilal in the last 16. While Guardiola has long supported the global growth of football, he acknowledged Klopp's frustrations and echoed concerns about the demands being placed on players.
Al Hilal delivered a dramatic 4-3 upset over Manchester City in extra time at Camping World Stadium, ending the Citizens' FIFA Club World Cup campaign and shattering Pep Guardiola's perfect record in the competition.
Bayer Leverkusen have secured a major coup by signing Liverpool's young defender Jarell Quansah, who arrived in Germany for his medical on Monday, fresh off England Under-21s' European Championship triumph.
Liverpool are set to make waves in the transfer market, reportedly targeting Newcastle United's Alexander Isak and Napoli's Victor Osimhen to revamp their attack for the 2025/26 season.
Liverpool are reshaping their defensive line with a clear focus on youth, as sporting director Richard Hughes prioritizes emerging talent over established names like Crystal Palace's Marc Guehi.
