Barcelona clung on to claim a hard-fought victory over newly-promoted Real Valladolid after a stoppage-time VAR review ruled out a late equaliser.
VAR was only introduced to La Liga this season and it was used to show that Keko’s diving header was offside.
The decision denied Valladolid a second point from two La Liga games.
Ousmane Dembele had fired Barcelona into the lead in the second half after Sergi Roberto kept the ball in play with a header on the byline.
Luis Suarez also had a goal ruled out for offside with 10 minutes remaining.
Barcelona began the defence of their league title with a 3-0 win over Alaves last weekend but were fortunate to cling on to victory over Valladolid – who finished fifth in Spain’s second tier last season.
Goalkeeper Jordi Masip made two impressive saves from Suarez and Philippe Coutinho before the break and former Manchester City forward Enes Unal was a constant threat.
The 21-year-old had an effort tipped over the bar in the first half and Keko came close to equalising with another header after the break.
The recently-laid pitch hindered both sides, with large divots appearing throughout the match forcing players to attempt to replace patches of turf in an attempt to make it smoother.
The hosts delivered a crushing blow to Barcelona’s title hopes when they last played at the Estadio Jose Zorrilla four years ago, winning 1-0 against a team which included Lionel Messi, Neymar and Cesc Fabregas.