After dominating Pep Guardiola's side 3-0 in last week's first-leg at Anfield, the Reds qualified courtesy a dominating 5-1 aggregate against a team that has dominated English football in recent years.
Guardiola admitted he was concerned by the appointment of Mateu after he took charge of City's game against Monaco in the last-16 last season and booked Sergio Aguero for a dive when he was caught by goalkeeper Danijel Subasic in the penalty area.
There is one man to thank for all of this: Klopp.
"But whoever we get will find it hard to come to Anfield and score some goals".
Over £500 million on transfer fees alone has been pumped into preparing City's squad for the latter stages of the Champions League in two seasons under Guardiola. "I was not overly happy at halftime to be honest", said Klopp.
"I think we made a step forward in terms of personality to play these kinds of [Champions League] games, like I never said before", he added.
City's European exit capped a wretched week, which also saw them blow the chance to clinch the Premier League title on Saturday when Manchester United came from two goals down to beat their bitter rivals. They're a good team, they're always going to put you under pressure, we knew that.
He added: "Liverpool can not match the experience of battle-hardened Champions League campaigners like Real and Bayern".
"You can not imagine how much intensity you feel before a game like this", he said.
Liverpool do of course have a rich Champions League history, most recently with the miraculous comeback in the 2005 Champions League final against AC Milan in Istanbul, although the Italians gained revenge in the final two years later.
"It was quite hard tonight, again especially with the start".
"We can only develop", said Klopp.
"To be honest I was shouting a bit at half-time".
Attacking ace Mohamed Salah also spoke after the game and explained how Liverpool struggled to counter the Citizens' high press in the first half. We are here and we deserved it, and I am really happy about that.