Manchester United are Manchester United again. Winning trophies, playing exciting football and on course for Champions League qualification. Yet their ability to use this summer as a stepping stone towards Premier League and European success has been compromised by a damaging combination of prolonged failure, commercial flat-lining and even their partnership with a Russian airline.

Sources at United and UEFA have told ESPN this week that the club are expecting to comply with financial fair play (FFP) regulations this year, but as recently as January, football director John Murtough went on the record to say that United were focusing on being "financially disciplined and compliant with FFP rules." Murtough's comments at a fans' forum were a clear signpost to the challenges that lie ahead.

United's road map back to the top is by no means without hazards. They face a number of obstacles this summer, including a difficult balancing act to ensure that they comply with FFP, even if the club goes into the transfer window with new owners.

Even if a new owner arrives to succeed the Glazer family, United will be boxed in by all of the negative factors that have squeezed their transfer budgets over their years of decline.

United travel to Liverpool on Sunday aiming to win at Anfield for the first time since January 2016. They will also face Jurgen Klopp's team believing that, after almost a decade, it is they who are in the ascendancy while their traditional rivals are facing a difficult period of transition and perhaps even decline.

Liverpool need to rebuild an ageing midfield, with Borussia Dortmund's Jude Bellingham their No. 1 target, but the prospect of missing out on Champions League qualification this season (they are six points behind fourth-placed Tottenham Hotspur with a game in hand), added to their owners' ongoing pursuit of new investment to help fund projects on and off the pitch, has left the club staring at an uncertain future.

Throughout their equally illustrious histories, United and Liverpool have rarely been successful at the same time. When one has been dominant, the other has often endured a lengthy period of upheaval. With United ending their six-year trophy drought by winning the Carabao Cup last Sunday, it would seem that their time is coming again under coach Erik ten Hag just as Liverpool prepare for a downturn.

But it is by no means certain that United can, or will, kick on. Quite simply, for United's numbers to stack up, the off-field team at Old Trafford needs to perform as well as Ten Hag and his players have done recently in order to give the club the space in the finances required to deliver the reinforcements that could make United competitive in all competitions next season and beyond.

United will need to offload a number of players to create additional funds and clear space on the wage bill. Club captain Harry Maguire, Victor Lindelof, Scott McTominay and Anthony Martial could leave. Goalkeeper David de Gea, whose contract expires this summer, has already been told he must take a substantial drop to his existing £375,000-a-week deal if he wants to stay.

The commercial team, led by chief executive Richard Arnold, must also re-energise the club's commercial revenue streams. In basic terms, the more revenue United can generate, the more they can spend on improving the playing squad.

Since peaking at £363.1 million in 2018, United's annual commercial earnings had dropped to £313.5m in 2022. Like all clubs, United have had to overcome the impacts of the COVID-19 pandemic, but they are unquestionably earning less from their off-field deals.

When United agreed a five-year shirt sponsorship deal with TeamViewer in 2021 worth £47m-a-year, it marked a substantial drop on their previous £64m-a-year agreement with Chevrolet. United announced earlier this season that they are ending the TeamViewer deal early, with ESPN reporting in January that Arnold led a commercial team at the Davos economic forum with the intention of securing a new, world-record shirt deal.

United are also still without an airline partner, 12 months after cancelling their £5m-a-year deal with Russian flag carrier Aeroflot following the invasion of Ukraine. While £5m may seem a relatively insignificant figure for a club of United's stature, when added to the £17m drop in income from Chevrolet to TeamViewer, it creates a sizeable hole, especially when the Old Trafford wage bill rocketed to a record high of £384m last year.

Declining commercial revenue, escalating player salaries and the lack of playing success, which in turn reduces broadcast revenues and prize money, have diminished United's once formidable earning power.

By the 2025-26 season, new UEFA regulations will restrict clubs to spending 70% of total revenues on transfer fees, wages and agents' fees. This season that figure is 100% of revenue, dropping a further 10% each year.

With United forecasting overall revenues of between £590m and £610m this season, it is already evident that there can be no repeat of last summer's £229m spending spree, especially with the club needing to reduce its balance of £307m in outstanding transfer payments, too.

With sources telling ESPN that Ten Hag has made a new centre-forward the club's priority this summer, United are likely to have to trade before they can contemplate moving for Tottenham's Harry Kane, Napoli's Victor Osimhen or Juventus forward Dusan Vlahovic. But United won't be able to take the Chelsea route of signing new players to unusually lengthy contracts of seven or eight years in order to spread the cost of their fees, with UEFA set to place a five-year limit for FFP calculations in response.

In many ways, United face the challenges that the majority of clubs must overcome. They will have to make every pound count and justify whatever they spend and, ultimately, that is good, sensible business.

But in modern football, when clubs at the top spend fortunes to stay ahead, being sensible and sustainable doesn't seem like the quickest way to get there.

For Manchester United, though, they have no other option.