Two second half goals from Luis Suarez sealed a first Champions League win of the season for Barcelona at home to Inter Milan.
Ernesto Valverde's side drew 0-0 at Borussia Dortmund in their first European game of 2019-20, but they picked up a first win of the season against Antonio Conte's side, thanks to a dramatic turnaround.
Lautaro Martinez handed the Serie A side a shock 1-0 lead at the Camp Nou, as he tucked away Alexis Sanchez's square pass.
Barcelona looked to rally as the first half wore on, with Suarez and Antoine Griezmann both forcing saves from Samir Handanovic before the break.
The defending La Liga champions looked to force the issue in the second half, with substitute Arturo Vidal playing a key role in their comeback.
The Chilean international created an angle for a cross just before the hour mark, with Suarez volleying home his pass from just inside the box.
With Conte's side looking to contain Barcelona in the closing stages, it was to be the genius of Lionel Messi and Suarez that unpicked the Serie A leaders.
Messi's run from deep created space for the Uruguayan international, who finished powerfully past Handanovic from the edge of the box.