Barcelona came from two goals down to beat Real Sociedad 4-2 on Sunday, ending a 10-year wait for a win at Anoeta in La Liga.
Barca won in San Sebastian last year in the Copa del Rey but had failed to win in each of their last seven league games there, dating back to 2007: losing five and drawing two.
It looked like history would repeat itself when Willian Jose and Juami fired the hosts into a 2-0 lead, but two goals from Luis Suarez, one from Paulinho and a Lionel Messi free-kick secured the three points for Ernesto Valverde's side.
As a result, Barca restored their nine-point point lead over Atletico Madrid and extended the gap between themselves and Real Madrid to 19 points. They are also unbeaten in all competitions in 29 games now.
The home side started the stronger in the San Sebastian rain and took a deserved lead in the 11th minute. Xabi Prieto's cross was met brilliantly by Willian Jose, who shook off Paulinho and saw his header bounce beyond Marc-Andre ter Stegen's reach.
Willian Jose should have had a second moments later when his deflected shot from 18 yards deceived Ter Stegen. However, referee Jose Luis Gonzalez deemed Ivan Rakitic, questionably, had been fouled moments before. Barça were let off the hook.
Only temporarily, though. Eventually La Real doubled their lead in the 34th minute. It had been coming. Sergio Canales brilliantly picked out Juanmi, who had ghosted in from the left. The forward's shot deflected off Sergi Roberto and beyond Ter Stegen.
Barça would have taken the half-time whistle at that point. But they kept going and somehow found themselves back in the game in the 39th minute. Luis Suarez found space on the left and squared for Paulinho, who turned home his eighth league goal of the season. Game on.
With the rain lashing down, Barca dominated the second half. They equalised via an attack led by Sergi Roberto. The right-back passed to Messi, who fed Suarez. There was still a lot of work to be done, but the striker produced a brilliant chipped, curling finish from the corner of the box.
The same player then gave Barca the lead, latching on to a Thomas Vermaelen clearance and sending Geronimo Rulli the wrong way.
And the three points were sealed by Messi. The Argentine scored a stunning free-kick from 30 yards to leave Barca as the only unbeaten side in Europe's top five leagues after Manchester City were beaten on Sunday at Liverpool.