Ferencvaros briefly got back into the game when Ihor Kharatin scored from the spot in the 70th minute after Gerard Pique was sent off for bringing down Tokmac Nguen. However, even with 10 men, Ronald Koeman's side were too strong for their visitors and late goals from substitutes Pedri and Ousmane Dembele put the gloss on a comfortable win.
Messi led this Barca performance, scoring one and setting up another, but it was the performance of the younger generation which will excite the club's supporters. There were two 17-year-olds on target in Fati and Pedri, while Francisco Trincao, 20, did well on his full debut on the right wing.
It took Barca a while to get going but once Messi gave them the lead they oozed confidence. Coutinho's goal came at the end of a six-minute spell of sustained possession as the Catalans zipped the ball around in a way that will have pleased Koeman.
Pique and Clement Lenglet struggled to deal with Nguen's speed all night and it ended up with Pique getting needlessly sent off. With Barca 3-0 up, he didn't need to take Nguen down but he did, earning a red card and giving a penalty away in the process. What's worse, he will miss next week's game in Turin against Juventus.
Manager rating out of 10
7 -- Koeman finally found the right balance in attack. With Fati left and Trincao right, Barca weren't so predictable. The input of substitutes Pedri and Dembele also showed that he's managing to keep all his attacking options motivated.
Player ratings (1-10; 10 = best. Players introduced after 70 minutes get no rating)
GK Neto, 6 -- Despite conceding from a penalty and seeing Ferencvaros, who posed a threat on the break, hit the bar, he didn't have many difficult saves to make.
DF Gerard Pique, 5 -- Didn't need to make the foul which saw him sent off. Barca had already won the game -- and Ferencvaros scored from the penalty anyway.
DF Clement Lenglet, 6 -- Like Pique, struggled with Nguen's pace, but stepped up in the final 20 minutes when Barca were a man light.
DF Sergino Dest, 7 -- The United States international looks completely at home in this side already. Played an hour at left-back and the final 30 minutes at right-back.
MF Miralem Pjanic, 6 -- The minutes were more important than the performance for the Bosnian midfielder on his full debut for his new club.
FW Francisco Trincao, 7 -- Took a while to get going but showed plenty of trickery and technique once he did. Provided a threat on the right that Barca haven't had this season.
FW Philippe Coutinho, 6 -- Took his goal well and was heavily involved in the play but often dallied on the ball instead of making simple passes.
FW Ansu Fati, 8 -- Not 18 until the end of the month, he became the youngest player to score two goals in the Champions League. Followed up his strike with a good assist for Coutinho, too.
FW Lionel Messi, 9 -- Unstoppable when he got going. Beat three players before winning the penalty which he converted to open the scoring and make it goals in 16 consecutive Champions League campaigns. After that, Barca relaxed, and he was central to all their best moments, including setting up Dembele's goal.
FW Pedri, 6 -- An unforgettable night for the 17-year-old, who scored his first goal for Barcelona on his Champions League debut.
DF Junior Firpo, 6 -- Made his first appearance of the season after returning from a hamstring problem.
FW Ousmane Dembele, 7 -- Showed great pace and decision-making to set up Pedri's goal, before taking his own goal really well late on.