Enzo Maresca says that Chelsea "are not ready" to compete for major trophies against Manchester City and Arsenal this season.
The Blues have made a strong start to life under Maresca, losing just two of their 10 matches so far.
They are currently on a five-match winning run in all competitions, most recently seeing off Gent 4-2 in their Conference League opener on Thursday.
So far, Chelsea have scored 27 goals under the Italian, with 15 of those coming in the league, outperforming their 12.2 expected goals (xG), and only failed to score in their opening Premier League match against City.
However, Maresca has insisted people should not get carried away by Chelsea's recent form, playing down their chances of lifting any silverware this campaign.
"I really don't think we can compete with City or Arsenal," Maresca said.
"I really don't think that, because we are not ready. The reason is that City has worked with the same manager for nine years and Arsenal for five years. If you want to compete for big things, you need that time.
"After Arsenal beat PSG [in the Champions League] they asked Luis Enrique, and he said the same thing, that Arsenal have had the same manager for five years and [PSG] only a year and a half.
"Imagine us, only three months… so it's a huge difference. So, I am really convinced we cannot compete with those clubs."
Before Maresca's appointment, Mauricio Pochettino only spent a season at Stamford Bridge, while Graham Potter before him was only in the position for just under seven months.
After another busy transfer window for Chelsea saw them bring in 13 players, Maresca has urged for patience as they continue to find their footing in the early stages of his tenure.
"The target is to improve and slowly, slowly to get closer to those clubs but at the moment we are not ready for that," he added.
“There is no timeframe because you can continue to improve and add solutions to things always.”
Chelsea face Nottingham Forest at home on Sunday in their final match before the international break.