Pep Guardiola hadn't even arrived yet, but already Jurgen Klopp had a warning for him anyway.
“We knew about it," said the latter in January 2016 midway through his first season on Merseyside, "but to feel it is different.”
More than 18 months on, it's a line that still seems so relevant for both men. When Klopp delivered it, he was speaking amid speculation of Guardiola's approaching move to Manchester City, where many expected him to dominate based on the evidence of his stints at Barcelona and Bayern Munich.
But the charismatic Liverpool boss saw it differently. He was in the early stages of the transition Guardiola would soon encounter and was discovering just how difficult it was. England and the Premier League wasn't like elsewhere - nothing like elsewhere, in fact.
Despite arriving with glittering CVs and huge reputations, both Klopp and Guardiola have both found adapting to the relentlessness and intensity of the in-your-face Premier League extremely challenging.
At times, both managers have had their respective sides playing some of the most exciting football the division has seen, and yet neither have managed to mount a serious title challenge.
Both would have been aware of the Premier League's unique depth and competitiveness, but awareness in this case has proven to be little more than that. As Klopp said: "To feel it is different.”
Even with their sought-after schemers, both City and Liverpool have succumbed to those lower down the table. Both have been unsettled by opponents happy to buck fashionable trends. Both have found the slog harder than they'd anticipated.
Naturally, then, there's a genuine intrigue surrounding Guardiola and Klopp as they prepare to meet at the Etihad Stadium on Saturday. It's only early in the new season and oddly these are the sort of games in which both have thrived, but there's a pressure on each of them to deliver on the promise their arrivals represented. And the early indications are that they're ready for it.
Both Guardiola and Klopp have overseen fast starts for their sides this season, the football at times beautiful, even if not completely flawless.
The Spaniard's revamped squad has hinted at an attacking power that could be unstoppable as cohesion develops, with David Silva and Kevin De Bruyne leading the charge in particular, and clinching top-15 spots after three weeks in the Goal Pressure Index, presented by Sure and powered by Opta data.
Klopp, meanwhile, has continued assembling the most frantic of outfits, a side defined by energy above all else.
The addition of Mohamed Salah gives further bite to a front line now unquestionably led by Sadio Mane, who, currently third in the Goal Pressure Index with a season score of 90/100, might hold the key to the Reds' title ambitions.
If the array of attacking talent between these sides sounds scintillating, it's because it is. The same goes for the potential of these teams. And yet Guardiola and Klopp meet on Saturday still looking to turn that potential into something more.
The pressure to deliver is on.