Leonardo Jardim revealed his frustration at working with such a young team after Monaco scraped an unconvincing 1-0 win away to Gazelec Ajaccio in Ligue 1 on Sunday.
Jardim's side needed a first-half Fabinho penalty to secure all three points in Corsica against the newly promoted club as they claimed their first victory since the opening day of the campaign.
"We are happy to win but all these young players are going to be the death of me. Our youngsters in midfield and attack missed a lot of chances," Jardim told reporters after the match.
"Our objective is to play good football but it's not easy. These young players have come from small clubs, where they are not used to playing with pressure to finish towards the top of the table. But our job is to work with them and help them progress."
Monaco lost a host of key players over the summer, including Geoffrey Kondogbia, Yannick Ferreira Carrasco and Anthony Martial -- the latter joining Manchester United just before the transfer window closed for an initial fee of £36 million.
Seven summer signings featured against Gazelec, including Fabio Coentrao, who made his debut from the bench after arriving on loan from Real Madrid.
However, 11 members of Monaco's matchday squad were aged 21 or under and Jardim says he will need time to build a competitive team again.
"When I arrived, Martial was on the bench. During my first six months, he continued to be a replacement," he said. "But then in the last five months he reached a good level.
"That is the intention for those who have just arrived. They have only been here a month. I don't have a magic wand."
Monaco travel to Anderlecht on Thursday to play their opening Europa League group-stage game.