Jurgen Klopp admits he is desperate to prevent Louis van Gaal getting one over him when Liverpool host Manchester United on Thursday.
The Europa League tie at Anfield was described as one of the biggest tests he will face as Liverpool manager and pits him against an old foe in United's Van Gaal.
Klopp also defended his counterpart after the wave of criticism he has faced this season, but said there would be no mercy shown.
"I don't believe in enemies in football, I believe in real football opponents," Klopp told his prematch news conference on Wednesday. "I've absolutely nothing against Louis van Gaal but it's the last thing I want that he wins.
"You can be best friends but for 90 minutes you must forget that. It's the mother of football games, that's what you want when you are young.
"It's a big challenge but the best thing you can do in football. It's big, I don't have to compare. If you work in Dortmund and play Schalke, it's not possible to talk about anything else -- and it's similar here. I hope it's not the biggest game in my Liverpool career but it's very important."
Van Gaal has been unfairly maligned by critics, Klopp said, before adding that he felt confident given his past record against him when the Dutchman was Bayern Munich manager and he was at Borussia Dortmund.
"He's one of the most successful managers in the world," said Klopp. "We played against him a lot of times when he was at Bayern. First time maybe we lost -- probably we lost -- but then we learned, found the Bayern style and had the longest winning run against Bayern in the history of German football, I think five games.
"I'm pleased for him that he's changed fortunes because after a long career it's not OK that a few of you gave him the idea he knows nothing about football.
"We want to make their problems bigger, but they have changed enough that we don't have to be sorry for Man United."