Maresca’s side were in danger of an embarrassing loss at the Tofiq Bahramov Stadium in Baku after falling behind in the first half.
Estevao Willian gave Chelsea an early lead but Leandro Andrade equalised before Marko Jankovic converted a penalty to give the Azerbaijani minnows hope of a famous upset.
Former Manchester United winger Garnacho came off the bench to bail out the Blues with his composed finish after the interval.
Both sides have seven points from their first four matches in the league phase, leaving them in contention for the top eight finish that secures automatic qualification for the last 16.
“I think the big difference was inside the box. Again we conceded silly goals that we could avoid and we could probably finish better with most of the actions that we created,” Maresca said.
“When we conceded the first goal, they were with 10 players. I think it is quite silly to concede this kind of goal. Then we conceded the penalty, so the second half is more difficult because you are 2-1 behind and you need to score.
“We need to defend better inside the box and probably need to attack better in the other box.” (AFP)
