Tuesday's Champions League triumph at Stamford Bridge kept the London club on course to reach the last 16 of the competition following a superb display of attacking football featuring a brilliant goal from teenage winger Esteval.
The 18-year-old Brazilian slipped inside defender Pau Cubarsi then glided across Alejandro Balde before letting fly with an unstoppable shot.
Estevao's strike came after Jules Kounde's own-goal had put Chelsea ahead, with Barcelona captain Ronald Araujo sent-off in the first half for a second bookable offence
Liam Delap scored Chelsea's third goal, his first goal since their pre-season Club World Cup triumph, to send the Blues into Sunday's clash with Premier League leaders and London rivals Arsenal in confident mood.
"It's a big win, especially because it was Barcelona, but nothing's changed in terms of what team we are and what we can achieve," said Maresca, whose side will cut Arsenal's lead at the summit to three points with another victory at Stamford Bridge.
He added: "Now we focus on the next one. The feeling was very good. At home with our fans, it's way nice to share this kind of moment. Now, next 48 hours completely switch off, have a rest, recover energy.
"We need to keep the momentum. It's much easier to recover energy when you win games."