Football fans could buy cheaper live broadcasts of Premier League matches from overseas after a ruling in Europe on Tuesday which could have wide-ranging implications for sport, media and entertainment across the continent.

The ruling followed a long-running courtroom battle that began when the English Premier League (EPL) took legal action against a Portsmouth publican for showing matches using an imported Greek decoder box and card.

The European court of justice (ECJ) said stopping consumers buying TV from overseas was contrary to EU free trade laws.

In its judgment, the ECJ said attempting to prohibit the "import, sale or use of foreign decoder cards is contrary to the freedom to provide services" and could not be justified either by the protection of "intellectual property rights or by the objective of encouraging the public to attend football stadiums".

Lawyers said the landmark ruling would allow customers to seek a better deal from overseas broadcasters who show all 380 EPL matches live, including 3pm Saturday kickoffs, compared with the 138 broadcast in the UK by BSkyB and ESPN – although there are doubts about how many people would do so in practice.

Karen Murphy, landlady of the Red, White and Blue pub in Southsea, which was at the centre of the case, celebrated at her pub amid a sea of TV cameras and reporters.

"It's been the battle of the little guy," she said. "These corporate people feel they can throw money at things and just win."

A spokesman for Smithfield Partners, which acted for two of the suppliers of imported decoders who were also joined in the case, said it was delighted with the far reaching judgment.

"We consider this ruling to be a significant step in creating fair competition across the internal market, reducing artificially inflated prices which vary across member states," he said.

But the ruling was not entirely one-sided. Even if individuals would be allowed to import broadcasts for personal use, the complex 49-page judgment appeared to include clauses that protect the EPL's right to stop pubs using overseas coverage.

It said the transmission of certain "protected works", including the title sequence, the EPL anthem and various graphics could only be broadcast in a pub with the permission of the rights holder.

Much will depend on how the EPL's right to defend its copyright is interpreted when the judgment is returned to the British high court for a final ruling in coming months.

"We are pleased that the judgment makes it clear that the screening in a pub of football-match broadcasts containing protected works requires the Premier League's authorisation – currently only Sky and ESPN are authorised by the Premier League to make such broadcasts," said a spokesman for the EPL, which has had a team of lawyers and advisers working on the case.

Ultimately, it may decide to sell its next set of rights deals on a pan-European basis to ensure that no overseas broadcasters can undercut its domestic deal.

Lawyers said there would be a big knock-on effect for other rights holders and potentially for other creative industries.

"The decision is likely to have a potentially bigger impact on other football broadcasters, other sports and across other media such as films and TV programmes currently distributed in the EU exclusively on a territory-by-territory basis," said Lewis Cohen, a partner at law firm Mishcon de Reya.

"For example, Uefa may have to rethink how it sells Champions League broadcast rights as there are quite big price variances depending on the territory."

Broadcasting revenues have underpinned the huge growth in EPL revenues over the past 20 years, with much of the money flowing to players and agents.

The current deal is worth £3.5bn over three years, with £2.1bn from domestic broadcasters and £1.4bn from overseas. It is believed that only £350m of that £1.4bn comes from mainland Europe.

The EPL is set to launch a fresh clampdown on pubs using overseas broadcasters, once the ECJ ruling has been ratified by the high court.

Pubs have continually complained that they are overcharged for Sky subscriptions, which is why Murphy originally sought an alternative.