From Cristiano Ronaldo's explosive interview to the public row with Jadon Sancho, Erik ten Hag's 18 months in charge of Manchester United has been filled with challenges. He's been presented with another in the form of new minority stakeholder Sir Jim Ratcliffe, chairman and CEO of Ineos. If the Dutchman wants to extend his stay at Old Trafford, he needs to convince the British billionaire that he remains the right man for the job.

It wasn't so long ago that, with the first bids to buy United lodged in February, supporters were demanding that prospective owners formally commit to keeping Ten Hag as manager. "Everyone can see the progress the team is making under Erik Ten Hag," read the final point of a statement issued by the Manchester United Supporters Trust (M.U.S.T.). "After the frustrations of the last decade, it is clear that enormous strides are being taken. Any prospective bidder needs to explicitly commit to backing Erik and his plans to restore United to glory."

But that was more than 10 months ago, a time when United were winning games and challenging for trophies. By contrast, the 2023-24 campaign has started with 14 defeats in 28 games. When M.U.S.T. issued a statement in response to the Christmas Eve announcement of Ratcliffe's deal to buy a 25% stake, there was no mention of Ten Hag, 53, or their previous demand to keep him in the post.

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Fan support for Ten Hag has dwindled since February, when United knocked Barcelona out of the Europa League and won their first trophy in six years by beating Newcastle United in the Carabao Cup final. Given the shift from a position of strength to their current decline, there's a growing chorus openly advocating for a change after an early exit from Europe, along with humbling defeats to West Ham and Nottingham Forest over Christmas.

Assuming control of all football operations as part of his $1.3 billion agreement with the Glazer family, Ratcliffe is set to delegate the day-to-day duties to Ineos confidants Sir Dave Brailsford, Ineos director of sport, and Jean-Claude Blanc, former CEO of Juventus. Like supporters, their faith in Ten Hag is said to have diminished over the course of negotiations with the Glazers. Initially seen as bullish about the former Ajax boss in October, when Ratcliffe and Ineos moved into pole position following Sheikh Jassim bin Hamad Al Thani's withdrawal from the bidding process, the noises coming from the new part owners are not quite as emphatic.

Since a run of three consecutive wins against Brentford, Sheffield United and FC Copenhagen in October, Ten Hag has overseen just five victories in 15 games. Since the beginning of December, it's five defeats in eight, and this dramatic dip in form has come at a bad time for Ten Hag, who will sit down with Ratcliffe and his team for the first time at Carrington on Wednesday in a position of weakness.

Brailsford and Blanc are keen to revamp the football side, and Ten Hag -- already faced with the challenge of fitting into a new way of working, with new bosses -- will struggle to be forceful with his own demands when his team are eighth in the Premier League table.

Sources have told ESPN that Ten Hag is reluctant to give up any power in the new structure, especially his major role in the identification of transfer targets. He's guaranteed a veto on all transfer decisions under the terms of his contract, but his influence has extended beyond that, leading to United signing a number of his former players or those with links to Holland.

There are particular questions about Antony, a player Ten Hag pushed for after working with him at Ajax from 2020 to '22, but has since done little to justify the huge 85m transfer fee. A mediocre player signed for big money and handed a long deal on massive wages is exactly the type of thing Ineos wants to avoid.

Ten Hag doesn't have to look far to see the tensions that can exist in a working relationship between a new owner and an inherited manager resistant to change. Thomas Tuchel, a Champions League winner in 2021, was sacked by Chelsea in September 2022 after working with new owner Todd Boehly for just 100 days. Tuchel saw Boehly's demand for more engagement with club bosses as unnecessary interference, while there were also disagreements over the potential signing of Ronaldo and the organisation of a gruelling summer tour.

Boehly took charge at Stamford Bridge in May 2022, and Tuchel was sacked just seven games into the new season.

Sources have told ESPN that Ineos' preference is to keep Ten Hag until at least the end of the season, although there's an acceptance that more poor results may force it to act sooner. Graham Potter, who was approached by Ineos to take over at its French club OGC Nice in the summer, has been informally sounded out about his plans for the future, and Blanc has been inundated with calls from agents pushing the claims of their clients.

Ratcliffe's stake is set to be officially ratified by the authorities in early February; his team, headed by Brailsford and Blanc, will use this interim period to learn about how United operates and develop a plan to move the club forward after a decade of failure on the pitch.

Speaking at his first news conference following the announcement of Ratcliffe's deal, Ten Hag said the news was "positive" and that he "wants to work with" the Ineos team. The more pressing question, though, is whether, in the long term, they want to work with him.