Jose Gaya opened the scoring in the fifth minute with a stunning strike from distance, but Ansu soon dragged Barca back into the game. The Spain international levelled the scores with a fine solo effort in the 13th minute and then drew a spot kick that Memphis Depay converted just before half-time. Substitute Philippe Coutinho completed the scoring late on as Barce moved up to seventh in the table.
After one win in six and back-to-back defeats before the international break, the most important thing for Ronald Koeman's side here was to win the game. Not just to break that barren spell, but to get them back on track ahead of important games against Dynamo Kiev and Real Madrid this coming week at Camp Nou.
In that sense, it was job done, while there were also elements of the performance that will have pleased Koeman. The big one, of course, will have been Ansu's display as he made his first start since last November after recovering from a knee injury. He looks sharp and his relationship with Depay will be key if Barca are to rise up the table in the coming weeks.
The cherry on the cake was a debut for Sergio Aguero, who came on as a late sub after suffering a calf injury in preseason.
Barca need to switch on from the start. There was little they could do about Gaya's thunderbolt, admittedly, but it continues a trend of conceding early goals. Granada and Benfica also scored in the first five minutes against them, while it took Atletico Madrid just over 20 minutes to breach their backline.
Manager rating out of 10
6 -- Koeman returned to the 4-3-3 formation that most people at the club would like to see Barca play, and it served him well. It helps that he has more options in attack now, with Ansu and Aguero returning to boost the team's firepower.
Player ratings (1-10; 10 = best, players introduced after 70 minutes get no rating)
DF Gerard Pique, 6 -- Had a tough battle with Maxi Gomez and was well beaten by Guedes at one point, but he survived. Was in the right place at the right time to intercept a dangerous Carlos Soler cross late on.
DF Eric Garcia, 7 -- Two red cards and plenty of criticism have marked his return to Barca so far but he hasn't let it get to him. Read the game well, made some key interceptions and was good in possession.
DF Jordi Alba, 6 -- Linked well with Ansu on the left and was a threat in attack on his return from injury.
MF Sergio Busquets, 6 -- Was more like the Busquets on show for Spain in the UEFA Nations League than the Busquets we've seen for Barca so far this season. In the right system, he can still excel.
MF Gavi, 7 -- Another mature performance from the 17-year-old, although he needs to ease off on snapping into some challenges. That's four bookings in eight games for Barca.
FW Sergino Dest, 6 -- Played further forward as a right winger but was hesitant in attack, unlike in midweek when he rifled in a goal for the United States. Did well to help create Coutinho's goal, though.
FW Memphis Depay, 6 -- Acted as the wall to set up Ansu's goal and later slammed a penalty into the side netting. However, lost the ball too many times in possession.
FW Ansu Fati, 8 -- Hit the side netting, scored a stunning goal, won a penalty and brought a fine save from Jasper Cillessen. All in just under an hour as he continues his return from a long-term injury.
FW Philippe Coutinho, 6 -- Took too long on the ball at times but the goal could boost his confidence ahead of a big week for Barca.
DF Oscar Mingueza, N/R -- Replaced Sergi Roberto to help Barca over the line late on.
MF Nico Gonzalez, N/R -- Koeman once again showed faith in the young midfielder by introducing him with the game delicately balanced at 2-1.
FW Sergio Aguero, N/R -- Came on once Coutinho settled the game.