Arsenal's new signing Alexandre Lacazette is irreplaceable, according to the coach of Lyon, who sold the forward to the Londoners last month.
Lyon have been hit by an exodus of top players during the close season including Corentin Tolisso, Mathieu Valbuena, Maxime Gonalons and Rachid Ghezzal.
But none is more damaging than the loss of 26-year-old Lacazette, the club's top scorer in each of the last four seasons.
"We can't replace Alex. We've bought Mariano (Diaz), who has different qualities, and we have young players with different qualities too," said Bruno Genesio.
"We're going to have to compensate collectively for his departure."
Lacazette was Ligue 1's top scorer in 2014/15 and finished second to Paris Saint-Germain stars Zlatan Ibrahimovic and Edinson Cavani over the subsequent two years.
He bagged 91 league goals and 113 in all competitions over the last four seasons, convincing Arsenal to splash out £52 million ($68 million, 58 million euros) to sign the France international.
Lyon finished fourth in Ligue 1 last season and will play in the Europa League during the coming campaign, with the final of that competition played in their own stadium in May 2018.
"That needs to be a positive pressure," said Genesio.
"We can't be over-motivated or allow that to create negative waves by saying we have to win or have to be in the final because it's in Lyon.
"It's a great opportunity for us to play in a first European final, and on top of that it's at home.
"It needs to transcend the team and not create a pressure that inhibits us."
However, Genesio said the main aim was to ensure the team would not be playing in that competition the following season.
"The priority is to get back into the Champions League. A club like ours, in terms of investment, facilities and players, should be in the Champions League."