Christian Benteke's winner for Liverpool against Bournemouth on Monday should not have stood, the Premier League has confirmed.
His first goal for the Reds was awarded despite team-mate Philippe Coutinho being in an offside position.
The offside rule was amended this summer to emphasise players need not touch the ball to be ruled offside.
The Premier League has now written to all top-flight clubs clarifying the new interpretations of the rule.
Cherries boss Eddie Howe had earlier contacted referees' chief Mike Riley seeking clarification.
The rules state: "A player in an offside position shall be penalised if he; 1. Clearly attempts to play a ball which is close to him when this action impacts on an opponent or; 2. Makes an obvious action which clearly impacts on the ability of an opponent to play the ball."
In the incident in question, Benteke turned in a deep cross from Jordan Henderson at the far post after the ball flew past a clearly offside Coutinho, but referee Craig Pawson whistled for a goal.
The League's statement used stills from the match to illustrate the rules and underneath it said: "Expected outcome: Offside offence."