Maurizio Sarri conceded Lazio are set for a season of "suffering", and that he would have left "any other club" due to the Biancocelesti's transfer ban.
Sarri returned to the club for a second spell in June, 15 months after resigning from his first stint in charge.
However, it was only after signing a two-year contract that the 66-year-old was made aware of Lazio's transfer embargo, which prevented them from making any signings during the recent window.
"What I've done for Lazio, I wouldn't have done for any other team," he told reporters ahead of Sunday's clash with Atalanta.
"I would have walked away from any other club that told me the transfer market was closed after I signed the contract. The sporting director told me we'll probably be able to operate in the transfer market in January, but I don't have any official confirmation.
"Here, I had serious doubts about leaving despite the difficulties, and that strength hasn't left me. I still firmly believe I can help this group grow. Our campaign will be one of suffering. We're improving in training. Hopefully, that will be enough.
"Our situation becomes more difficult as time goes on. We need the humility to accept the struggle, but we must not confuse humility with accepting defeat."
Lazio have collected seven points from their opening six matches, three fewer than Atalanta who, along with Juventus, are one of two unbeaten teams in Serie A this season.
Head coach Ivan Juric, who replaced Gian Piero Gasperini in June, praised his side's "enthusiasm" and has called for unity ahead of a busy period for La Dea.
"Games between Atalanta and Lazio have always been great contests," he said. "Lazio are a side with plenty of quality and technical ability. This season, they've added pace, too, which makes them really dangerous.
"The team has shown enthusiasm right from the start. With seven matches in 22 days ahead, we'll need everyone."
Riavvolgiamo il nastro di #AtalantaLazio al 2010
— Atalanta B.C. (@Atalanta_BC) October 18, 2025
Rewinding Atalanta v Lazio to 2010#GoAtalantaGopic.twitter.com/DrM461iMHQ
PLAYERS TO WATCH
Atalanta – Mario Pasalic
Since his arrival at Atalanta in 2018-19, Pasalic has scored a league-high 48 Serie A goals as a midfielder.
If he finds the net in this match, he will become only the second midfielder to score more than one goal in each of the last eight Serie A seasons, after Inter's Hakan Calhanoglu.
Lazio – Matteo Cancellieri
Cancellieri has been Lazio's man in form in their last two matches, during which the Biancocelesti have collected four points – more than in their opening four matches of the season.
The winger has scored three goals, including a brace in the entertaining 3-3 draw with Torino before the international break.