Igor Paixao forced home Feyenoord's winner as they took a 1-0 aggregate lead in this round 16 playoff tie.
“You win games with duels, aggression, and Feyenoord had all those ingredients tonight,” admitted Conceicao on Sky Sport Italia.
“We should’ve done more, we also knew it was going to be a fiery atmosphere and they always give more on home turf. It’s the Champions League, this atmosphere should motivate us more, not less.
“There was immediately a Tijji Reijnders chance, then we conceded a goal with incidents that can happen in football, but we had the chances to equalise and should’ve done more. It is not over yet, it is wide open for the second leg and we certainly need a different response on Tuesday.
“We must all, starting from me, give a little more, raise the level and then games will be easier. I have a squad of technical quality and we must bring in other characteristics that are very important, otherwise it becomes tough.
“It is difficult to change it, but not impossible. We are here to make the last four months of the season different to the six that came before.”