Liverpool boss Jurgen Klopp hailed Manchester City boss Pep Guardiola as "a really influential manager" but suggested his time in the Premier League will prove to be the sternest test of his coaching credentials.
Klopp and Guardiola played out a head-to-head record of four wins apiece while in charge of Bundesliga giants Borussia Dortmund and Bayern Munich and will clash on English soil for the first time when Liverpool host City at Anfield on Saturday.
The Merseyside club are a point and a place ahead of their visitors in second, with both teams on a run of three consecutive wins having wobbled during the early weeks of December.
City reeled off six straight victories at the start of the season but have struggled to replicate such domineering form since and Klopp views the peculiarities of the English game, along with the demands that Guardiola's playing style places on his squad, as combining to provide a taxing challenge for his rival.
"Guardiola has his clear philosophy. They were in a good way [at the start of the season], then something happened," the German told a pre-match news conference.
"They are successful, but this league is difficult, a lot of challenges every week.
"He's a really influential manager. He has a clear idea. He had a fantastic career until now; nice style at Barcelona, really good at Bayern. Now at City, he has to show how good he is.
"He's very influential, the Barcelona style is not possible for every club to play, it depends on the players you have. If a Sunday league team tries to play like Barcelona, it's very difficult."
City have leading marksman Sergio Aguero back from a four-match suspension and Klopp demanded razor-sharp concentration from his defence as they seek to quell the free-scoring striker.
"He had three and a half weeks off, nice. He's back and a good striker," he said.
"I always thought he was a talented boy, but I never made a secret of it. Even without him, they're an outstanding team.
"It's only one thing, he can only score goals if we give him the ball. We need to be concentrated, that's the biggest challenge in this game.
"It's for both teams, hopefully, the same - they'll have the same problems with us."
Liverpool will again be without Philippe Coutinho with an ankle injury but Klopp believes the game will come down to fine margins in the battle not to lose further ground on ominously placed leaders Chelsea.
"Both teams are good on counter attacks, both teams are good in possession, so we have to defend," he added.
"The details will make the difference. I'm not sure, it's nice to think about, try everything you can to win the game.
"What I like is that we beat them last year, unfortunately we lost the [League Cup] final.
"They have got better since last year, we are getting better. It will be interesting.
"They will not play like last year, it's really exciting. If I was not on the bench I would buy a ticket, 100 per cent, for this game."