Barcelona's first Europa League game since 2004 ended in a 1-1 draw after coming from behind against Napoli in the first leg of their knockout round play-off.
Xavi's side travel to the Stadio Diego Maradona next week needing a win to advance to the last 16.
The first half-chance of the game fell the way of Barcelona just before the fifth minute after they won the ball back high up the pitch, but Pedri was unable to keep his half-volley down.
Alex Meret made an instinctive stop at his near post to deny Nico Gonzalez shortly after before full-debutant Pierre-Emerick Aubameyang had a speculative shot curl just wide of the Napoli net.
Napoli nearly hit their hosts against the run of play when Piotr Zielinski slipped through Victor Osimhen, but Marc-Andre ter Stegen got down low to deny the Nigerian.
From the resulting corner, Ter Stegen released Pedri on the counter, in turn playing one over the top for Adama Traore to chase, but Kalidou Koulibaly made a great recovery challenge just in time - though replays suggested any goal would have been ruled out for offside.
Barça should have taken the lead just before the half-hour mark when Aubameyang released Ferran Torres but his shot was woeful, and they were made to pay when Napoli went down the other end and put themselves ahead.
Zielinski's initial low strike was saved by the feet of Ter Stegen, and the Poland international reacted quicker than the flailing Gerard Pique to the rebound to fire into the roof of the net.
That goal seemed to knock the stuffing out of Barcelona, who looked toothless for the remainder of the half and badly needed regrouping at the interval.
Barcelona were handed a lifeline after the break when they were awarded a very soft penalty after a VAR check, with Traore's cross brushing the hand of Juan Jesus. Torres stepped up and converted to level the tie.
Xavi's men now had their tails up and were buoyed on by a crowd of over 73,000. Aubameyang went close after a driving run from midfield but his strike sailed over the bar, while Torres had a free-kick sail into row Z.
Torres spurned yet another great chance to put Barcelona ahead minutes from time after Pedri's neat flick, with the winger losing his composure and horribly skewing his shot.
With time running out, Luuk de Jong nearly sealed a memorable finish with an audacious overhead kick, but it fell just the wrong side of the post.
Dries Mertens nearly stole a win for Napoli in stoppage time but fired straight at Ter Stegen before Torres again missed the target from close range.
But Luciano Spalletti's men held on to secure a draw ahead of the return leg next Thursday.
FC Barcelona player ratings vs Napoli
1. Goalkeeper & defenders
Marc-Andre ter Stegen (GK) - 5/10 - Kicking was a bit off and he didn't exactly cover himself in glory for Zielinski's opener.
Oscar Mingueza (RB) - 7/10 - Took up some decent positions going forward but his technique was lacking at times.
Eric Garcia (CB) - 7/10 - Surprisingly the more senior of Barcelona's centre-backs.
Gerard Pique (CB) - 4/10 - Slow to react to Zielinski's initial strike and was generally off the pace.
Jordi Alba (LB) - 5/10 - Wasn't actively bad but he didn't stretch the play as everyone knows he can.
Frenkie de Jong (CM) - 5/10 - Recycled possession well but couldn't find a cutting edge.
Nico Gonzalez (CM) - 8/10 - A pretty complete midfield performance, winning the ball back, progressing it and creating chances.
Pedri (CM) - 8/10 - Sensational on the ball but lost the run of Zielinski for the opener.
Adama Traore (RW) - 4/10 - The same old story for Traore, who gave defenders the runaround in areas that weren't dangerous before failing with his delivery. Very fortunate that one of his poor crosses won a penalty.
Pierre-Emerick Aubameyang (CF) - 7/10 - Worked hard for the team, made some great runs and openings, but lacked that ruthlessness in front of goal that he's forged a career out of.
Ferran Torres (LW) - 3/10 - Scored a penalty, sure, but Torres was a net-negative for Barcelona. Horribly missed a series of gilt-edged chances, gave the ball away needlessly and played with little confidence.
Gavi (CM, 65' for Nico) - 5/10 - Didn't quite have the same impact as his fellow youngsters.
Ousmane Dembele (RW, 65' for Traore) - 6/10 - Booed and whistled with every touch by at least some sections of the crowd. May have affected him as he wasn't initially great in his cameo but came to life in the last few minutes.
Sergio Busquets (DM, 65' for De Jong) - 6/10 - Just a little bit smarter than De Jong.
Sergino Dest (RB, 81' for Mingueza) - 5/10
Luuk de Jong (85', CF for Aubameyang) - 6/10