At a press conference the Justice Commissioner Vera Jourova said the action was "not revenge" for decades of anti-EU headlines and support for Brexit from The Sun, but officials will be well aware they have attacked Murdoch at a time when the future of his media empire is in the balance.
The suspected sports rights cartel under investigation is understood not to relate to Sky directly, although Britain's dominant pay-TV operator does buy some rights from its biggest shareholder, such as the cricket World Cup.
Nevertheless, any suspicion of new wrongdoing in the Murdoch empire as its long pursuit of full control of Sky enters the final stretch provides its critics with yet another peg on which to hang their objections.
They have already made hay from phone hacking and sexual harassment at Fox News.
The addition of potential antitrust violations could make for a toxic mix as British regulators prepare their recommendations for the Culture Secretary Matt Hancock.
As news of the raid reverberated through Europe's broadcasting sector yesterday, a picture began to emerge of what is an investigation in its early stages.
The dozen or so investigators that swooped on Fox's offices in west London did so at an opportune moment, if they intended to pore over the company's files without the supervision of senior executives.
The senior ranks of European broadcasting are gathered in Cannes this week for the annual MIPTV jamboree, a trade event at which rights deals are sealed over fine wine and Mediterranean sunsets.
It is understood that Jan Koeppen, head of Fox Networks group in Europe and Africa, was not present for the raid.
A former Sky Deutschland executive, he was promoted two years ago to oversee a business that comprises dozens of channels and online services across two continents.
Among his biggest businesses is the European arm of Fox Sports.Sports rights, already a Fox mainstay, are due to become a central focus for the Murdoch family when their plan to sell most of their other entertainment assets to Disney comes to fruition.
Regardless of any potential indirect impact on the Sky deal, Brussels scrutiny of their dealings in the sporting arena will be unwelcome.
Eyebrows have already been raised in sports broadcasting over Fox's unheralded deal with Fifa in 2015 for rights to the 2026 football World Cup.
Unusually, it appeared that the football's governing body awarded the rights without any competitive bidding.
The European Commission's competition watchdog confirmed it is investigating Fox and other media companies over sports rights in a late-night statement rushed out after news of its raid was made public.
It gave a hint as to the nature of the investigation by citing Article 101 of the EU's central treaty, which outlaws cartels.
It leaves open several possibilities, however. The legislation prohibits a host of cartel behaviour and restrictive business practices, including price fixing and collusion with purported competitors to divide up markets.
There are rules to outlaw imposing conditions on some buyers but not others in similar deals. Forcing buyers into unrelated deals as a condition of purchase is also banned.
In the complex market for buying and selling sports rights across borders, for a business as large as Fox Networks any of these potential violations is possible.
Fox said it its co-operating fully with the investigation.It owns rights to a host of top sports across the continent, according to monitoring by the media analysts Ampere.
Fox owns the pan-European rights to US sports including NFL football, NHL ice hockey and major league baseball. It is also embedded in homegrown sport with rights to top flight German football in Italy and the Netherlands.
Fox's links to Dutch sport are particularly tight. It owns the domestic rights to top-flight football via a 51/49 joint venture with Eredivisie, the equivalent of the Premier League.
Fox is also responsible for selling the rights in other territories including Italy.
The Netherlands appears to be an early focus for Brussels' competition watchdogs.
Yesterday it emerged that VodafoneZiggo, a cable and mobile telecoms joint venture between Vodafone and Liberty Global, the owner of Virgin Media in the UK, was raided at the same time as Fox.
Ziggo carries Fox Sports Eredivisie on both its cable TV service and its online streaming service. It also has its own premium sports channel, however, Ziggo Sport, which competes with Fox and owns the Dutch rights to English Premier League and Championship matches, as well as the UEFA Champions League.
A spokesman for Ziggo said: "We have been informed that the European Commission is inspecting several media companies in Europe, including Ziggo Sport."
Ziggo Sport is fully co-operating with the European Commission's inspection and are unable to comment further at this stage."
Although the European Commission described the raids as a "preliminary step" in its investigation, its decision to turn up unannounced in London was widely viewed as a sign of the seriousness of its suspicions.
Alex Haffner, head of competition law at Fladgate, said: "The fact that the EU Commission chose to exercise their 'dawn raid' powers is notable here. The Commission will typically only use such powers in cases where it believes it is necessary to take immediate action and has strong suspicions that unlawful activity has taken place, often as a consequence of a 'tip off' from an aggrieved third party."
The rights of defence mean that the Commission have a higher bar in terms of their grounds for suspicion before they can open their investigation."
Haffner, who advised the Premier League when it faced a European competition investigation a decade ago over its exclusive deal with Sky, suggested the European Commission could be looking at rights contract terms that restrict consumption of broadcasts and streams to one EU country."
The Commission has been looking carefully at issues concerning the way rights are exploited across borders within the EU and the extent to which consumers have freedom to access services wherever they are within the single market.
Some might inevitably question whether these investigations are in some way linked to those ongoing investigations," he said.
Regardless, as well as providing a new weapon to Murdoch's political opponents, the raids have handed an advantage to Comcast as it seeks to disrupt the Fox takeover of Sky with its rival £22 billion ($42.3b) bid.
As it courts the independent holders of the 61 per cent of Sky not controlled by Fox, the US cable giant has sought to emphasise the low regulatory risks of its approach.
Whether the CMA or the Culture Secretary Matt Hancock take the European action into consideration as they deliberate on whether to approve the Fox deal remains to be seen.
British competition watchdogs are at least fully aware of the suspicions. They accompanied colleagues from Brussels as they searched Fox's offices.
This story was first published by the Daily Telegraph and reproduced with their permission
