Manchester United are in a complete mess.

They have won only once in the league this season, and even their dramatic 4-4 comeback against Aston Villa on Sunday could not lift them out of the bottom three.

To make matters worse, manager Michael Carrick is reportedly on the verge of being sacked, with the club's hierarchy considering another managerial change. Reports are saying, it could be Mauricio Pochettino.

For a club that once dominated English football under Sir Alex Ferguson, the situation is almost unimaginable.

Former Manchester United captain Roy Keane believes part of the answer lies in a rather unusual place.

A horse!

Yes, you read that right.

Keane recently revisited a controversial chapter in United's history involving Ferguson, two wealthy Irish businessmen and a racehorse named Rock of Gibraltar.

What did Roy Keane say?

During an October 29 episode of Stick to Football, Keane questioned Gary Neville about how the Glazer family came to own Manchester United.

"How did the Glazers get involved in the first place?" Keane asked.

Neville, who has repeatedly called for the American owners to sell the club, wanted to focus on United's current problems.

But Keane was determined to revisit the past.

"There's a horse involved in this, you know what I mean?" he said.

"No one wants to talk about the horse. Can we talk about the horse? The horse is key."

So, what exactly happened?

How a racehorse changed Manchester United's history

The story goes back more than two decades and involves Ferguson and two Irish businessmen, John Magnier and JP McManus.

Ferguson was a passionate horse racing enthusiast and had developed a close friendship with the businessmen, who were also major shareholders in Manchester United.

At the centre of the controversy was Rock of Gibraltar, a hugely successful racehorse that won seven consecutive Group One races.

Ferguson was listed as a part owner of the horse alongside Magnier's wife, Susan.

However, things turned ugly when the horse retired from racing in 2002.

Ferguson believed he was entitled to a share of the horse's valuable breeding rights, which could potentially generate millions of pounds.

Magnier disputed that claim.

What began as a disagreement between friends eventually turned into a bitter legal battle.

How the Glazers entered the picture

The dispute soon spilled into Manchester United's boardroom.

Magnier and McManus began questioning Ferguson's conduct, including matters relating to transfer dealings.

Their relationship with the United manager deteriorated, and the dispute eventually ended in an out of court settlement.

But the damage had already been done.

In 2005, Magnier and McManus sold their substantial stake in Manchester United to American businessman Malcolm Glazer.

The deal proved crucial in allowing the Glazer family to take control of the club.

Their takeover was controversial from the beginning, particularly because of the enormous debt placed on United.

Of course, the club continued to enjoy tremendous success under Ferguson, winning five more Premier League titles and the Champions League in 2008.

But things changed dramatically following his retirement in 2013.

United have since struggled to rediscover their former dominance despite spending huge sums on players and repeatedly changing managers.

Was a horse really responsible for United's downfall?

It would be extremely illogical and unfair to blame Manchester United's entire decline on one horse or Ferguson's disagreement with its owners.

The club's problems are far more complicated, involving years of questionable recruitment, managerial changes and decisions at boardroom level. The ownership is just trying to milk the holy cow as much as they can.

But the Rock of Gibraltar dispute played a part in creating the circumstances that eventually led to the Glazer takeover.

And that is the connection Keane wants people to remember.

More than two decades later, United find themselves fighting near the bottom of the Premier League, with another manager facing the sack and supporters growing increasingly frustrated.

For a club that once set the standards in English football, it is a remarkable fall from grace.

And while a racehorse certainly cannot be blamed for everything that followed, Rock of Gibraltar will forever remain part of the story of how Manchester United's fortunes changed. What a story.