Rayo Vallecano fought back to draw with Barcelona, who dropped points in La Liga for the first time this season in a match hampered by problems with the video assistant referee (VAR) technology.

Teenager Lamine Yamal gave Barcelona a 40th-minute lead with a penalty the 18-year-old had won after being brought down by home defender Pep Chavarria.

However, there was controversy as VAR was not working at the time, meaning the decision could not be reviewed.

Marcus Rashford made his third appearance for Barca since his season-long loan from Manchester United, coming on in the 62nd minute for Raphinha.

The England forward had been substituted in their previous match at half-time when Barcelona were 2-0 down to Levante, but fought back to win 3-2.

While Rashford struggled to make an impact in a lively atmosphere and on a poor-quality pitch, he did send over a superb corner that was headed over by Eric Garcia.

Rayo equalised in the 67th minute through substitute Fran Perez's excellent volley following a corner.

Jorge de Frutos had a chance to put the hosts ahead, but had his shot saved with only goalkeeper Joan Garcia to beat.

After Rayo had a goal ruled out for offside, the Barca keeper made a fine late save to deny Sergio Camello.

Reigning Spanish champions Barca had won their first two La Liga matches, but are now fourth with seven points from their three games. Real Madrid and Athletic Bilbao are two points clear at the top after three successive wins.

What happened with the VAR technology?

BBC Sport's Spanish football expert Guillem Balague, speaking on Premier Sports, explained what happened with the VAR system and said: "The referee had to tell both managers [before the game started] that he could not get the VAR pictures, they were not getting into the stadium. When that happens, if there is an incident, he can't go and see the pictures.

"It looked after 11 minutes the assistant was saying 'we've got the pictures back', but I can tell you soon after they were lost again.

"So, at the point of the penalty, there's no possibility of looking at the replay of it on VAR as it was not working. But everyone knew about it, the captains and the managers, so the complaints is not so much that the referee could not see it, but that Rayo Vallecano felt it was not a penalty.

"But when you look at it in detail, it looks like the referee made the right decision."