Carlo Ancelotti was pleased with his side's attacking show at the Emirates, but says they will never win if they continue conceding goals like they did on Sunday.
"The performance offensively was really good, a lot of opportunities, but defensively really poor, we conceded three goals, it is not acceptable to concede three goals like this, and normally you lose the game," he said.
"We were able to equalise at the end of the first half, and we knew because they played Thursday they could lose energy, and they did, and we had opportunities to score, but the key point is we concede three goals too easy. This is the reason.
"To be good you have to attack well, we did, but you have to defend well, we didn't. I cannot be satisfied with this. To win here you have to do both.
"The good thing about this is we can be clear about what we have to do this week!"