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Sergio Conceicao admitted he is still trying to "find the right balance" after using all four of AC Milan's strikers together in the 1-0 defeat at Feyenoord.

Milan will now have to overturn the first-leg deficit at San Siro if it wants to reach the last 16 of the Champions League.

Igor Paixao profited from a Mike Maignan mistake as the goalkeeper let in his shot from a tight angle in the third minute. It proved the match-winner for Feyenoord, who defied the odds having sacked head coach Brian Priske on Monday.

All four of Santiago Gimenez, Joao Felix, Rafael Leao and Christian Pulisic started on Milan's front line, but they struggled to create chances of note.

In the first half, the quartet had just three shots worth 0.19 expected goals (xG), while they had just 14 touches in the opposition box.

They finished the game with 0.57 xG, only marginally less than Feyenoord's 0.58, but did not truly test Timon Wellenreuther. Tijjani Reijnders came closest, firing just over the crossbar.

"We tried to prepare for this the way we would a Champions League Final," Conceicao said. "I know how hard I worked to get here. I've been a player before and then a coach for 14 years. I respect lower league and Champions League opponents the same way.

"Everyone is an ideal analyst in hindsight. It was what I thought before the game. I realise people are curious about those four, but there were another seven players too. 

"I am the one who must find the right balance in the team, and I need to work on that."

Milan remains winless in its last 12 away games in the knockout stages of the Champions League (drawn four, lost eight), failing to score in eight of those matches. 

In fact, the Rossoneri have lost 44 percent of their away games in all competitions this season (P16 W7 D2 L7), their worst loss rate in a campaign on the road since 2013-14 (46 percent).

Milan will play at home in the second leg of their play-off on Wednesday, and Conceicao is expecting a much-improved performance.

"You win games with duels, aggression, and Feyenoord had all those ingredients tonight," he said."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."