New coach Francesco Calzona made his debut for Napoli with a 1-1 draw against Barcelona in the first leg of their Champions League last 16 clash on Wednesday, while Porto claimed a 1-0 stoppage-time win over Arsenal
Barcelona forced Napoli goalkeeper Alex Meret into several saves in the first half, but only found their breakthrough in the 60th minute, when Robert Lewandowski squeezed a low effort into the net.
Napoli, however, kept the match-up wide open as Victor Osimhen put the Italians back in contention for a quarter-finals spot with a 75th-minute equalizer.
Ilkay Gündogan could have scored a last-minute winner for Barcelona, but his effort went centimetres wide.
"We will head home quite sad because of the final score. I really believe that we could have won this," Barcelona defender Ronald Araujo told broadcasters Movistar.
In the other game, Porto and Arsenal were set to end their meeting with a goalless draw, but Galeno, who hit the post in the first half, scored in the fourth minute of stoppage time to give the hosts a dramatic win.
Barcelona got to business early in the game with 16-year-old Lamine Yamal. His first effort went wide in the fourth minute and his left-footed strike was then denied in the eight by Meret.
The goalkeeper was Napoli's hero in the first half, keeping his net clean when Lewandowski flicked the ball to the goal in the 22nd and Gündogan unleashed a powerful strike immediately after.
Napoli appeared to have taken control of the game in the final stages of the opening half, but it was Barcelona to get their opener after the break.
Pedri waited until Lewandowski had enough space before delivering a clever ball, which the Polish striker controlled before squeezing the it inside Meret's right-hand post.
And when tiredness seemed to be getting the better of some Napoli players, Osimhen put them back in the game, using his strength to beat the defender and then coolly slot it past the keeper in the 75th.
Barcelona could still have taken a win back to Spain in stoppage-time, as Gündogan recovered a loose ball after an effort from Lewandowski and fired a low strike from outside the box, but the ball went agonisingly wide of the post.
"We'll give everything we've got in Barcelona to get through to the quarter-finals. We showed we are a powerful and competitive side here tonight," Araujo said.
Porto were stopped by the post as Galeno had the first chance of the game in the 21st and his second attempt in the rebound went just wide.
Arsenal were off target in the 35th, but that was their closest opportunity as William Saliba tried to finish off Bukayo Saka's corner.
It looked for most of the second half that the game would finish in stalemate, but Porto found the net with only seconds remaining before the final whistle.
Arsenal lost the ball in midfield and Galeno collected it before firing a finish across David Raya's goal and into the far corner.
"We have to manage much better. We cannot win with the way we handled the ball on three occasions in deep areas. If you want to be in the quarter-finals you have to beat your opponent and this is what we will have to do at the Emirates now," Arsenal manager Mikel Arteta told TNT Sports.
"We lacked threat. We lacked aggression, especially with the ball in the final third. We can do better," he added.
The second leg games are on March 12. On Tuesday, Inter Milan defeated Atletico Madrid 1-0, while Borussia Dortmund were held to a 1-1 draw at PSV.
