Dries Mertens scored an unbelievable goal and put Napoli in front of Barcelona at the half time. That's his 121st goal for Napoli in all competitions.
Napoli counts a lot on defense. They don't let the ball near their goalkeeper's area.
The goal of Mertens was unstoppable. He put the ball right into the top corner and made it impossible for ter Stegen to catch it.
Mertens was forced off just eight minutes into the second half of the game, after challenge from Sergio Busquets.
Referee Felix Brych showed only a yellow card, but the Spain's World Cup winner will miss the second leg.
In the 57th minute, Antoine Griezmann scored his first away Champions League goal since February 2017. He made the scoreline 1-1 after an assist from Nelson Semedo.
Arturo Vidal got a red card after the referee shown him two quick yellow cards.
Quique Setien will have to go without Arturo Vidal and Busquets when this two team will meet again.
Barcelona will look to protect that away goal in the second leg which will be on March 18 at the Nou Camp.