Quique Setien's side was insipid in the first half and deservedly went behind to Dries Mertens' superb strike after 30 minutes at the Stadio San Paolo. Mertens went off injured in the second half, and it was obvious that the home side lost some of their essential attacking edge, for minutes later, Griezmann finished emphatically at the end of a fine team move.
Arturo Vidal was sent off with a few minutes remaining, having received two yellow cards in the same incident. He and Sergio Busquets – who was booked for the high tackle that put Mertens out of the game – will miss the second leg.
Here are the three things we learned as Barcelona drew 1-1 with Napoli in the Champions League.
3. Barcelona's away blues continue
Barcelona have not won the Champions League since 2015, and the Blaugrana have been terrible away from home in the knockout rounds over the last few years. Since defeating Arsenal 2-0 in the round-of-16 in 2016, Barcelona have won just one of their next nine away matches in the knockout round, with their narrow 1-0 victory over Manchester United last year the only reprieve in the last four years.
During that time, there have been heavy defeats to PSG and Juventus, Roma and Liverpool, while another loss was also recorded at the Vicente Calderon to Atletico Madrid in the 2016 quarterfinal, with clashes against Lyon, Napoli, and Chelsea ending in stalemates in the round-of-16.
By contrast, their home form has been impeccable (Barca have not lost at Camp Nou in the Champions League since 2013) but in light of their recent eliminations, getting the job done away from home is imperative to continental success.
2. Mertens is a Napoli legend
Dries Mertens came into this game one goal shy of Marek Hamsik’s goalscoring record of 121, and little had he imagined he would equal the record and be just shy of legendary status by the end of the night. The 32-year-old took one touch to control and another to set himself, before curling a stunning strike past Marc Andre ter Stegen who barely saw it fly past him.
This was a real work of art, as smooth as a painter’s brushstroke, a strike so sweet, no one could do anything. Genaro Gattuso had a plan for Barcelona, and his team played it out to perfection. Rather than try to play Barcelona at their game, Gattuso picked players he thought would be able to excel on the night, and it worked.
Allan, Piotr Zielinski, and Fabian Rui gave a performance that their manager would have been proud of in his playing days, while Kostas Manolas acted as the defensive lynchpin in the absence of the ever-reliable Kalidou Koulibaly.
1. Barcelona are their own worst enemies
While the away goal gives Barcelona an edge over Napoli, their already thin squad seems to have got thinner for the second leg. Both Vidal and Busquets will miss the return leg at Camp Nou, and Gerard Pique limped off late on after an awkward fall saw him roll over on his ankle.
With the El Clasico this weekend, Quique Setien has a lot of work to do in the next couple of weeks. Barcelona hold the advantage in theory, but with their squad problems, there is still a great chance for Napoli to spring an upset.
Barcelona completed 724 passes on Tuesday night and somehow waited 57 minutes for their first shot on target, which Antoine Griezmann subsequently buried. They ended the game with just two shots on goal. Napoli defended admirably and everybody knows this isn’t the Barca of old, but surely Setien can be braver instead of asking his players to pass in a U-shape for 90 minutes.