Barcelona and Valencia went in at half-time level in their top-of-the-table encounter thanks to a terrible decision by the linesman.
The Catalan giants - unbeaten since their Super Cup defeat to Real Madrid in August - kicked off on Sunday night four points clear of 2nd placed Valencia.
Valencia finished 12th in the 2016/17 La Liga standings but have won eight consecutive league matches to keep the pressure on Barca.
Their was plenty of anticipation leading up to the game but the main talking point of the first half was a decision made by the referee.
Fans on social media were up in arms at an incredible call by the officials.
Messi's disallowed goal
Leo Messi hadn't scored in each of his last five outings but was sure he had broken the deadlock in the 30th minute.
His shot from outside the box was parried into his own goal by Neto and Messi's Barcelona teammates wheeled off celebrating.
The Valencia players were also waiting for the referee to blow his whistle... but the linesman incredibly deemed the ball had not crossed the line and play continued.
Gary Lineker reacts
The Match of the Day host was far from impressed by the horrendous decision by the linesman.
In the Premier League, the officials are not needed to make this type of call due to the successful implementation of goal-line technology.
Sergi Roberto's reaction sums up every Barcelona fan
The 25-year-old La Masia academy graduate saw his tweet go viral after sharing some emojis immediately after Messi's goal was not given.
La Liga has somehow still not introduced goal-line technology but will be introducing VAR (video assistant referee) at the beginning of the 2018/19 campaign.
Things went from bad to worse for Barcelona when Rodrigo gave the hosts the lead in the 60th minute.