Sarri's side suffered another defeat on Saturday at the hands of AC Milan, with the 2-0 loss leaving them in 14th place with seven points.
"We lost the game with a couple of strong runs from players with more pace than ours. I still think we are on the right track," Sarri told DAZN after the match.
"We had an impressive first half, but created many moves on the attack and didn’t even turn them into scoring opportunities."
Sarri must now shift his focus to the Champions League group stage and Wednesday's visit to Scottish champions Celtic.
"The Champions League is a luxury for us, our lives are in Serie A," he admitted.
"From Monday we will start to think about Celtic and give our all because it is an important spotlight."
Sarri provided an update on captain Ciro Immobile (33), who had been struggling with a muscle issue following their 2-0 home win against Torino on Wednesday.
The Italian played the last 15 minutes of the match against Milan in an attempt to get an equaliser.
"After meeting with the doctor, he did not feel ready to play," Sarri said.
"We decided together that in case of extreme need, he would try."
After Celtic, Lazio host the in-form Atalanta on October 8th.
