They are not friends, according to Arne Slot. “Friends is someone you see a lot and go out with for dinner with,” said the Liverpool manager. Erik ten Hag does not belong in that category. Their relationship, Slot claimed, is as “good and normal as with other managers”. But a rivalry has been renewed; it may not be personal between them, but it tends to be between their clubs.

They have been at the two biggest teams in their native Netherlands; now they are at the two most successful ever in England. It was Ajax against Feyenoord. Now it Manchester United versus Liverpool.

Ten Hag is both the more established and the man whose position has been in greater peril. He has won two trophies in England. He had to wait a couple of weeks after the second, May’s FA Cup, to discover he wasn’t being dismissed. United forever feel a work in progress, while regressing last season to their lowest-ever Premier League finish.

Slot, he suggests, has a better inheritance. Jurgen Klopp left a team who came third and who sustained a title challenge until April. Indeed, their chances of the quadruple were only ended by United at the end of March in the FA Cup. Liverpool finished 22 points above United last season, though that is partly an indictment of Ten Hag. They were the last Premier League club to make a signing this summer. “It is difficult for us to make the team even stronger,” said Slot, but United seem to have a permanent need for more players.

“Liverpool, it's clear, they are in a different phase of the lifecycle,” said Ten Hag. “They have a team that is mature, players who have been playing for a long time together and who are very experienced. I think the players, the partnerships, the relationships in that team are very clear and that is what he inherited. That has been built over the past years. We have much more of a mix and have to build a new team.”

Ten Hag suggests he got the harder task in taking over at United. His interim predecessor, Ralf Rangnick, said they required “open-heart surgery”. Ten Hag has referred to the “no-good” culture before his time. In its way, United will be the job of a lifetime.

“That was one of the reasons I wanted to come here, to have this challenge,” he explained. “I knew beforehand that this was the most difficult thing I would ever do in my life, to come into a club where there were a lot of problems, which we had to solve.

“I inherited a history from six years of no trophies that meant the dressing room and the qualities were not right. So we had to build, we had to construct, to perform and to bring up a higher level. We did this with transfers, but we also did it by bringing academy players into the team.”

Those younger players, such as Alejandro Garnacho and Kobbie Mainoo, have provided some of the greatest endorsement of Ten Hag’s management. Yet transfers have come at a cost: the arrival of Manuel Ugarte from Paris Saint-Germain will take his spending to around £600m, with £200m of it this summer. The figures for Slot are altogether smaller: his first signing, the £25m goalkeeper Giorgi Mamardashvili, was loaned back to Valencia, so it is only the £10m winger Federico Chiesa who will be available this season.

Ten Hag has spotted tactical shifts under the new regime at Anfield, but Slot is working with Klopp’s players. Were they all fit, his fellow Dutchman could pick a United XI consisting solely of his own signings and have several more on the bench. “What you see now is that we have brought new players in, many young players, and we are in a lifecycle from the start,” Ten Hag added. “We are still in the transition stage, we have young players and now we have to construct a team from it for the future.”

The counter-argument is that United cannot remain in transition forever. There are, nevertheless, legitimate reasons to argue they are there now, with the arrival behind the scenes of a new set of powerbrokers this year, whether Sir Jim Ratcliffe or Sir Dave Brailsford, Omar Berrada or Dan Ashworth – and with new voices in recruitment.

However, if Ten Hag’s logic is that United are a team for the future and Liverpool a side for now, their average ages this season are 25.9 and 26.4 respectively. And there can be a sense that, like many enemies, United and Liverpool have certain similarities. Liverpool have continuity in the team but a new face in the dugout, and United have the same manager but an ever-changing cast of players.

Ten Hag contrived to have a winning record against Klopp along with a 7-0 defeat. Now it is an all-Dutch battle, where Ten Hag has implied that Slot starts with an advantage.

Manchester United v Liverpool kicks off at 4pm on Sunday 1 September, coverage starts on Sky Sports Premier League at 3.30pm