Luis Suarez scored an 82nd-minute equaliser as La Liga leaders Barcelona maintained their unbeaten start to the season against Atletico Madrid.
Saul Niguez had put the hosts ahead on 21 minutes with a 25-yard curling drive into the bottom corner.
Lionel Messi hit the post with a free-kick early in the second half, before Suarez connected with Sergi Roberto’s cross to head in at the far post.
Barcelona are five points clear of Real Madrid, who earlier beat Getafe. Atletico are third on 16 points, a point behind their city rivals.
The game marked Barcelona’s first visit to the capital since the Catalan independence referendum on 1 October, which was opposed by Spain’s national authorities.
Atletico fans waved hundreds of Spanish flags inside the stadium and booed every touch by Barcelona and Spain defender Gerard Pique, who had given his public support for the referendum.
Barcelona did not have any “official” fans in the new 68,000 capacity Wanda Metropolitano due to “logistical problems” in the stadium.
It is the second La Liga game in a row that Barcelona have played without any fans, after their home game against Las Palmas on the day of the referendum was played behind closed doors.
Barca won at an empty Nou Camp amid widespread political unrest in Catalonia, after a request to have the game postponed was turned down.
Barcelona went into the game having won all seven league games this season and were almost ahead after 30 seconds.
Messi, who scored a hat-trick in midweek as Argentina dramatically qualified for the World Cup, exchanged passes with Suarez in the penalty area, but his low shot was deflected into the side netting.
Antoine Griezmann forced two excellent saves from Marc-Andre ter Stegen in the opening 10 minutes as Atletico set the early tempo, before they took a deserved lead.
Barcelona grew into the game in the second-half with Suarez and Messi forcing saves from Jan Oblak but the Slovenia goalkeeper could not keep out the Uruguayan’s equaliser.
Suarez celebrated by running towards the home fans, cupping his hand to his ear in celebration.