Manchester United's on-field results must improve if they are to retain their status as the world's highest-earning football club, according to a sports finance expert.
United, who are sixth in the Premier League table and 19 points adrift of leaders Liverpool after 17 games, sacked Jose Mourinho on Monday and have hired former striker Ole Gunnar Solskjaer on a caretaker basis for the remainder of the 2018-19 campaign.
Though they face a battle just to secure qualification for the Champions League next season via a top-four domestic finish in this campaign, United will still hope to once again come out on top of the Deloitte Football Money League - which ranks the world's biggest teams based on revenue generated - when it is released in the new year.
That is because the club has benefited from several lucrative commercial deals with global partners such as adidas, Chevrolet, TAG Heuer and New Era.
However, Daniel Plumley, a senior lecturer at Sheffield Hallam University who researches finance and governance of professional sports teams, has warned their results away from the pitch are linked to how they fare on it.
"All the research we've done here at the university would suggest that financial performance and sporting performance are inexplicably linked - you need to maintain that sporting performance to drive the revenues forward," he told Omnisport.
"You also need that to maintain a commercial presence in the marketplace. Manchester United's commercial presence is unrivalled - no one is saying that is ever going to go away - but to maintain that you need the performances on the pitch as well.
"The club were just not performing on the pitch and that's what we come down to here; we can't separate the two. They are linked. Whatever you do on the pitch will have a huge bearing on what you do off it financially."
Mourinho is not the only one who has been criticised for United's current predicament, with the board having come under fire for their transfer dealings and managerial appointments since Alex Ferguson retired in 2013.
Yet in the commercial sector they have made a number of high-profile signings. United have deals with an 'official global mattress and pillow partner' and an 'official global lubricant and fuel retail partner'.
"I know the board have come in for some criticism about Mourinho, but if you look at people they've got in high-profile positions, the ability they've got to still generate that kind of revenue from commercial streams whilst the performance on the pitch has not been so good is a testament to the business model," Plumley added.
"Let's not forget that the brand of Manchester United is still strong, they're one of the biggest clubs in the world. Despite all these on-pitch performance issues, we have still seen the brand grow."
That might change if United are continually absent from the Champions League - European football's top table.
"Let's say conservatively it's £30-50million if you don't qualify, that wouldn't be a huge problem for Manchester United to miss out on that for one season because their revenue profile is strong," Plumley said.
"If the club continually miss out on Champions League qualification then the value of the brand reduces, the attractiveness to sponsors reduces.
"Despite it being Manchester United, that is still the pinnacle of Europe. People want to be associated with that competition and the clubs within it, that's one of the biggest factors."
