Celtic were beaten but not disgraced as they warmed up for their crucial Champions League match against Astana with a loss to Barcelona in Dublin.
Barca took the lead in splendid style, Arda Turan placing a marvellous finish beyond Craig Gordon after 10 minutes.
A defensive blunder from Jose Antonio Martinez gifted Leigh Griffiths a leveller, but Efe Ambrose diverted a cross into his own net a minute later.
Munir Mohamed made it 3-1 to secure a comfortable win for Barca.
There was no suggestion of Celtic boss Brendan Rodgers fielding a weakened side ahead of the crucial Champions League third-round, second-leg qualifier on Wednesday.
Barca were without the likes of Gerard Pique, Andres Iniesta and Neymar for their first pre-season match, but Luis Enrique did include the towering talents of Lionel Messi and Luis Suarez.
James Forrest was on the bench for the match in Kazakhstan and may wish he had been on the sidelines at the Aviva Stadium after being embarrassed in the build-up to Barcelona's opening goal.
He was nutmegged and left for dead wide on the right by Aleix Vidal, who rolled the ball across the edge of the box for Turan to curl a sumptuous finish into the top corner.
The Scottish champions were gifted an equaliser just before the half-hour mark, with Leigh Griffiths able to fire home from close range after Jose Antonio Martinez's errant touch near his own goal presented the striker with a tap-in.
Barca regained the lead just a minute later, Ambrose turning Juan Camara's cross into his own net, before Suarez teed up Mohamed to make it 3-1 at the break.
With that Champions League qualifier looming, Celtic made seven changes at the break. And with the second half punctuated by further substitutions on both sides, the match became subdued, with very few chances on created on either side.
Barca left with the spoils, but Rodgers will feel it was a very useful outing for his men as they gear up for a vital 90 minutes at Celtic Park against Astana on Wednesday night.
Bitton injury concerns Rodgers
The Celtic manager was left concerned by an injury picked up by midfielder Nir Bitton, placing his participation against Astana in doubt.
"Disappointment we may have lost Nir Bitton so we'll see how he goes," Rodgers told Sky Sports.
"Looks like he's twisted his ankle which prevented him from being able to move so well in the first half. But other than that all the players have come through it well.
"Great experience for them and we'll be getting ready now for Wednesday."
Celtic: Gordon, Janko, Ambrose, O'Connell, Izaguirre, Brown, Bitton, McGregor, Roberts, Griffiths, Forrest.
Subs: Fasan (Gordon 45), Fisher (Izaguirre 77), Ciftci (Roberts 45), Dembele (Griffiths 45), Armstrong (McGregor 45), Christie (Forrest 63), Rogic (Bitton 45), Allan (Brown 45), Ajer (O'Connell 45), McCart (Ambrose 63), Ralston (Janko 63).
Barcelona: Masip, Vidal, Camara, Mathieu, Roberto, Martinez, Denis Suarez, Arda Turan, Luis Suarez, Munir, Messi.
Subs: J.Suárez, J.Martínez, Borja, Gumbau, Samper (Messi 45), Aleñá (Denis Suarez 61), Tello, Carbonell, Marlon (Mathieu 61), Mujica, Nili, Alfaro (Suarez 61).