Napoli coach Maurizio Sarri slammed his team's attitude after their loss to RB Leipzig in the Europa League on Thursday.
The Serie A leaders suffered a 3-1 home defeat, despite going ahead, to be left with work to do in the last-32 tie.
Adam Ounas had given Napoli a second-half lead, but Timo Werner scored either side of Bruma's strike to see the Bundesliga side grab the upper-hand.
Sarri was unhappy with his side's approach to the encounter, saying they failed to honour the Napoli shirt.
"I'm very disappointed with our attitude. My players seemed to be lacking hunger and enthusiasm. We were below par not just technically but on a mental level too," he said.
"We must change our mindset, especially in Europe. I'm sorry to say that the lads who played did not honour the shirt and that's a bad sign because we should have been thinking about the league from tomorrow, not tonight.
"It's not the first time we've let our concentration slip when playing in a cup competition. Maybe it's partly my fault, but I don't think we're mature enough yet to tackle certain games the right way.
"Leipzig are an excellent side: they have great technical ability and they're very well organised. We gave far too much away to the wrong opponents. We can't concede a third goal like that in stoppage time with two defenders in attack."
The result ended Napoli's five-match winning streak ahead of their hosting of SPAL on Sunday.
Sarri admitted the Serie A was his team's focus, but said that was no excuse for their performance.
"I'm not going to lie to anyone, least of all my players. We all know that Serie A is our number one priority but we simply cannot be producing performances as bad as this," he said.
"We have a lot of improvement to make in terms of our focus and consistency. If we're not 100 per cent focused, that's obviously going to have repercussions.
"I expect to see a strong response on Sunday because if we have any more lapses like tonight it's going to be tough in the league too."