John Royal of Oddies bar won his appeal after he was fined by Sunderland magistrates for showing games via Albanian television.
MPS was previously contracted by the Premier League to carry out investigations into the use of foreign satellite in pubs. The company went into liquidation in August 2013.
It is thought the decision may now open the floodgates for other licensees to get their convictions overturned.
Last year, the High Court has ruled that a prosecution brought by MPS on behalf of the FA Premier League against a pub in Cheshire was "incompetent".
At Newcastle Crown Court, Judge John Evans said: "Genuinely, this is the first time in my experience, either at the bar or as a member of the judiciary, that the prosecution authority has gone into liquidation.
"The reality is there is no one now to challenge this appeal. Accordingly, I will be making an order allowing the appeal, quashing the conviction."
A Premier League spokesman said: "Media Protection Services has gone into liquidation and we understand it is therefore unable to continue cases which it commenced that are currently in the legal system.
"This has no bearing on the fact that Sky Sports and BT Sport are the only legitimate broadcasters of live Premier League football in the UK.
"Our work in this area has increased significantly this season and we are currently taking legal action against a number of publicans who have used unauthorised foreign systems to show Premier League matches in UK pubs."
Premier League response
"Media Protection Services has gone into liquidation and we understand it is therefore unable to continue cases which it commenced that are currently in the legal system.
"This has no bearing on the fact that Sky Sports and BT Sport are the only legitimate broadcasters of live Premier League football in the UK.
"Our work in this area has increased significantly this season and we are currently taking legal action against a number of publicans who have used unauthorised foreign systems to show Premier League matches in UK pubs."