The Cottagers struck twice in the final 15 minutes through Harry Wilson and Rodrigo Muniz to cancel out Cole Palmer's early opener at Stamford Bridge.
Maresca said afterwards:
"It is a shame, especially in the way we lost the game in the last minute.
"It happened and now it is about recovering energy and ready to go again in a couple of days.
"We could have managed the game better, controlled better, but it is a game we can learn things.
"We have said many times we are a very, very young team but the most important thing is to see them growing and improving.
"Tomorrow we are in recovery and on Saturday we prepare for Monday game. It is important to recover the energy.
"I said many times no matter if we win games or don't it is more the reality we can see inside that for many reason we are not ready (to challenge for the title). The most important thing is to see the team improve."