The video assistant referee ended Leicester’s celebrations as their second-half goal was taken off the scoreboard, resulting in a 1-1 draw with Leeds at Elland Road.
Ademola Lookman thought he had netted home a winner midway through the second half, but he later learned he was standing in an offside position when Jamie Vardy had flicked on a Youri Tielemans corner.
Raphinha had put his side in front in the 26th minute when his free-kick caught out Leicester keeper Kasper Schmeichel at his far post.
Seconds later, however, Leicester responded with Barnes curling a stunner into the top corner from a tight angle.
Leeds then had multiple chances to win last on, with Jack Harrison somehow volleying the ball over from a few yards out, and Rodrigo missing a clear chance at the back post just before the hour mark.
Marcelo Bielsa’s team moved three points clear of the relegation zone, while Leicester stayed 12th.
Leicester have now gone four games without a win, leaving Brendon Rodgers’ side as far behind from West Ham in third as they are above Aston Villa in 17th.
They were fortunate not to have been at least a goal down at half-time with Leeds unable to convert the numerous chances they created. Despite drawing, Leeds manager Marcelo Bielsa said his side created “double the amount of danger” Leicester did.
Leeds now travel to Tottenham next week, while Leicester host top of the table Chelsea in what looks to be a difficult battle.