From the moment Abu Dhabi royalty stunned the soccer world by taking control of Manchester City in 2008 before swiftly offering huge sums for some of the sport’s most high-profile players, their ambition to make the club a true global power was clear. First, though, they had to become top dogs in their own city. When the local rival among a population of just 500,000 is already a member of soccer royalty, not to mention one of the richest sports teams on the planet, the challenge is far from straightforward.

Unlike Russian billionaire Roman Abramovich’s big splash into English soccer four years earlier with Chelsea, an already successful team in the nation’s glitzy capital, Sheikh Mansour and the Abu Dhabi United Group had assumed control of a club known for its spectacular way to lose rather than win. Less than 10 years earlier the club had been submerged in England’s third tier and was without a major trophy in 32 years. Manchester United, about to become the most successful club in English history, had just been crowned champions of Europe for a third time.

“It would be extremely difficult to surpass Manchester United in popularity,” Michael Colangelo, assistant director of USC’s Sports Business Institute said. “They are a globally recognized brand with partners both domestic and internationally. They are one of the premier brands in sports."

The two teams from England’s industrial heartland renew their rivalry at the Etihad Stadium on Sunday. And on the pitch, at least, much has changed in six years. In 2012, City came out on top in Manchester and in England in one of the most dramatic finishes to a title race in history. While United regained the Premier League a year later in legendary manager Sir Alex Ferguson’s last desperate act of his 27-year reign, City took it straight back.

After a season in which City finished 22 points and six places ahead of a flailing Ferguson-less United, the temptation is to see two clubs heading in opposite directions. But in soccer it takes more than a few years of success on the pitch to translate significantly off it.

“From a playing perspective the gap has completely closed,” Andy Green, a soccer finance expert with a particular focus on Manchester United, said. “From a financial perspective the gap has shrunk, but in true commercial terms -- i.e. ignoring MCFC's commercial deals with companies controlled by Abu Dhabi, it remains very significant. Manchester United is a global brand and Manchester City is not.”

City have certainly been working on their brand strategy in recent years. Two years ago the club turned to a man who had overseen vast commercial growth at Spanish giants Barcelona, Ferran Soriano, to try and do the same with the emerging power in Manchester. The numbers alone are impressive. Since their takeover, revenues have increased 311 percent to 271 million pounds ($434 million) in their last published accounts for the 2012-2013 season. By far the biggest part of that leap has been in commercial revenue, which has jumped from a meager 15.7 million pounds in 2008-2009 ($25 million) to 143 million pounds ($228 million) two seasons ago -- under 10 million pounds ($16 million) less than Manchester United’s in the same season.

However, as Green alluded, the true merit of those figures have been called in to question. A 350 million pounds ($559 million) 10-year deal with Abu Dhabi’s national airline has faced accusations of being overvalued in order to pass new Financial Fair Play (FFP) rules. Europe’s governing body UEFA, which introduced the regulations to try and limit clubs’ losses, appeared to say as much when fining Manchester City for breaching the rules this summer. City still made a loss of 52 million pounds ($83 million) in the 2012-2013 season, although that was down from 99 million pounds ($158 million) the previous year.

If they are to keep reducing losses and comply with FFP while remaining a force on the field, revenues must continue to prosper.

"The next step is to ensure a sustainable, long term revenue generating business continues in spite of the initial losses that were required to pay for large transfer fees and wages," Daniel Geey, a sports lawyer with Field Fisher Waterhouse, explained.

In attempting to meet that goal they will come up against their neighbors, but it is in a global rather than a local sense that the real battle will be waged.

“On a local level both brands might benefit from each other and need to cooperate under certain conditions; whereas on a global level they are competitors looking for the ‘same’ international fans, sponsors, media rights, and players, too,” Tim Ströbel, a visiting professor at Ohio University from Universität Bayreuth in Germany, said.

In recent years, City have expanded their international presence beyond what has become a common practice of playing exhibitions matches around the globe, by setting up off-shoot teams in other countries. The rebranded Melbourne City F.C. began play in Australia this year and next March New York City F.C. will enter Major League Soccer in the United States. Both teams will play in the same sky blue colors as Manchester City, a key indicator of the strategy to turn a new wave of fans onto City’s path.

“Maybe what they have to do is somehow generate new market share, whether its converting non fans to soccer, converting new fans to soccer who don’t have any connection to either team, or attracting fans outside of England, particularly in the U.S. and other countries that are late adopters of soccer,” Bob Dorfman, a sports marketing expert with Baker Street Advertising, said, reflecting City’s focus.

Perhaps most impressively, a club that was once famously derided by Ferguson as the “noisy neighbors” have been conducting their business in a much more savvy and even understated way than those from Old Trafford in recent times. Indeed, it is Manchester United’s ownership practices that are now under harsher spotlight. Long criticized for their debt-laden takeover of the club in 2005, the Glazer Family's strategy has come into even sharper focus since the retirement of the most successful manager in English soccer history in 2013.

“From 2008 to 2012, MUFC under invested in the transfer market and the owners have to take responsibility for this,” Green said. “Significant sums were spent on debt interest, bond buybacks and fees that should have been spent on the playing squad. The club over relied on the genius of Sir Alex Ferguson and upon his departure the scale of this under investment became clear. This shortsightedness has actually cost the club financially as it has scrambled to rebuild the squad since 2013.”

Indeed, in the past year, rather than City offering inflated sums for players, it was United, now with an aging squad and without the lure of participation in the Champions League, that were doing so -- obliterating their transfer record twice in the space of seven months.

Yet, even as the playing side has been struggling to maintain its lofty heights, commercially the club has broken new ground. On the back of a record $559 million seven-year sponsorship deal with Chevrolet signed in 2012 and that came into effect this season, United this summer inked an unprecedented 750 million pounds ($1.2 billion) 10-year deal with kit supplier Adidas. On their own, City’s worldwide appeal doesn’t yet come close to making such deals a reality.

"If City continue with their on-field success combined with deep runs into the Champions League along with stadium expansion which will increase corporate hospitality, there is every possibility in the years to come that City can grow their revenues further," Geey added. "Whether they can successfully commercialize their brand as well as United have done on a country by country, product differentiated basis remains to be seen."

It is City who are favorites to win on Sunday, but over the long haul evidence shows it will take more than a temporary swing to dethrone United as Manchester’s kings.