The two billionaire media tycoons have been involved in a series of disputes
Silvio Berlusconi's Italian broadcaster Mediaset is being anti-competitive against Rupert Murdoch's News Corp, a Milan court has said.
A judge ruled the Italian PM's media arm was preventing News Corp's Italian unit, Sky Italia, from buying ads on its television networks.
This was anti-competitive and illegal the judge said, but added he could not force Mediaset to take Sky adverts.
Sky, which brought the action, said it would resume talks with Mediaset.
Mediaset has recently expanded into pay television, which was formerly solely the domain of Sky Italia.
"The decision does not change the behaviour that companies of the (Mediaset) group have had so far," Mediaset said in a statement.
It added that the court decision only required that Mediaset was not biased in refusing to run Sky Italia advertising campaigns.
News Corp said it was "satisfied" with the ruling.
It had alleged that Mediaset was stopping it from buying adverts on the RTI and Pubitalia networks.
Mr Berlusconi is among Italy's richest men, estimated to be worth $6.5bn (£4.4bn) by Forbes magazine. Now serving his third term as Italy's prime minister, he controls Mediaset as well as AC Milan football club.
Mr Berlusconi has recently accused fellow billionaire media tycoon Mr Murdoch of mounting a personal attack on him via The Times newspaper over several scandals involving his private life.
News Corp, run by Mr Murdoch, owns pay TV broadcaster Sky as well as the Times and Sun newspapers in the UK and the New York Post and Wall Street Journal in the US.