Sergio Conceicao conceded that the absence of key players hit his AC Milan team hard during their 2-1 defeat to Napoli in Serie A on Sunday. 

Conceicao watched on as Matteo Politano and Romelu Lukaku fired Napoli two goals in front in the first half, but the Rossoneri responded after the break. 

But Luka Jovic's late goal proved to be a consolation as Milan failed to find a way through, with substitute Santiago Gimenez also seeing a penalty saved by Alex Meret. 

Milan now sit in ninth in the table on 47 points, nine points adrift of the Champions League places, though their cause has not been helped by recent injuries. 

Ahead of kick-off at the Stadio Diego Armando Maradona, the club confirmed that Ruben Loftus-Cheek was diagnosed with acute appendicitis and had undergone surgery. 

Malick Thiaw was also absent, while Rafael Leao, who replaced Warren Bondo in the second half, was struggling with an issue picked on international duty. 

"Since I've been here I've never made excuses, even though we played every three days until two weeks ago, but today absolutely everything happened," Conceicao said.

"The doctor called me to tell me that Loftus-Cheek had to undergo surgery, Thiaw had intestinal problems and Leao felt a little pain in his thigh. 

"I don't want to dwell on bad luck, even though it was a black day."

Conceicao also said his team needed to perform better after conceding twice early in the first half. 

Indeed, Politano's strike was only the second goal scored in the first two minutes of play by Napoli against Milan in Serie A, after Piero Golin's effort in March 1955.

But the Milan boss was pleased with his team's response in the second half, with the Rossoneri ending the contest dominating many of the match metrics. 

Milan ended the game with an expected goals (xG) total of 2.69 to Napoli's 0.96. 

"(Napoli) managed to escape our pressing too easily in the first half, but we rectified the situation in the second half and we did it with more courage and aggression," he said.

"We were missing something, I have a lot of confidence, the atmosphere in the group is healthy and I don't want to change it."

Milan now turn their attention to the Coppa Italia, where they face bitter rivals and Serie A leaders Inter in the first leg of the semi-finals on Wednesday.

"It's an important game, the Coppa Italia is one of the club's objectives," Conceicao added.

"The players have already shown they have character, we need to continue working on our balance.

"It's difficult for everyone in this position in the league table, but I have a group that wants to change these results."