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 Robertoâ€™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 Barcelonaâ€™s first visit to the capital since the Catalan independence referendum on October 1, which was opposed by Spainâ€™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 â€œofficialâ€ fans in the new 68,000 capacity Wanda Metropolitano due to â€œlogistical problemsâ€ 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.