Estevao had put Chelsea ahead in the 16th minute, hitting the back of the net with a low, near post effort as he struck for the second European appearance running. The Blues were expected to push on to secure a crucial three points in their bid to make the next round of the Champions League.
However, Chelsea's lead lasted just 13 minutes as Leandro Andrade hauled Qarabag level on the half-hour mark. And Qarabag were ahead shortly before the break as Marko Jankovic tucked past Robert Sanchez from 12 yards after Jorrel Hato, who was at fault for Andrade's equaliser, handled the ball in the Chelsea box.
Alejandro Garnacho, who came on for the second half, netted Chelsea's second in the 53rd minute, but despite a dominant display the Blues were unable to add a third and secure an away victory. The 2-2 draw leaves Chelsea as one of seven teams mired in mid-table with seven points from the opening four games.
And Maresca pulled no punches at full time as he criticised Chelsea's defence and attack in a game they really should be winning. "No, I think I said before, the big difference today for me was inside the box," Maresca said at his press conference.
"The goal we conceded, they are silly goals for me. In their box, for the amount of times that we arrived, we have not been clinical enough. So this is the big difference for me."
And on Hato, who endured a performance to forget at centre-back, the Blues boss added: "I think Jorrel, like the team, started very good. We were winning the game, we were in control.
"Then we started to make some mistakes that we need to improve and we need to avoid and for sure in the future we're going to avoid that."
Maresca opted for a triple change at the break as Enzo Fernandez, Liam Delap and Garnacho replaced Andrey Santos, Tyrique George and Jamie Gittens for the second half, while the Chelsea head coach was forced into an early sub as Moises Caicedo replace Romeo Lavia before Estevao's opener. Garnacho bagged his second Chelsea goal since his summer arrival from Manchester United to spare the Blues' blushes.
And on the decision to leave the former trio on the bench, Maresca said: "Again, when you start the game, the intention is always because you are sure that the ones that start the game, they are able to do the right things."
The former Leicester boss also reserved praise for Garnacho, who made Champions League history on Wednesday, adding: "Now, when you don't win, I can understand that it's always, but I think Garnacho, he has done well in the second half. We gave him the chance. He's slowly, slowly improving."
Lavia, who has endured rotten luck with injuries following his arrival from Southampton in 2023, came off after just eight minutes on his fourth start of the season. When asked how the Belgian is, Maresca said: "Yeah, we feel very ashamed especially for him because he's not able to be fit for a long, long period. We will see now as it's too early to understand what kind of injury. Hopefully it's not a big injury.
"No, I think it's a quad injury," he replied when asked if his withdrawal was due to a hamstring injury.
And the Blues welcome the manager-less West Midlands side to Stamford Bridge this weekend as they look to head into the international break on a high. Wolves sit rooted to the bottom of the Premier League table having collected just two points from the opening 10 games of the season.
A 3-0 loss at Fulham cost Vitor Pereira his job as Wolves head coach and after Gary O'Neil ruled himself out of the running to succeed the Portuguese boss, Rob Edwards and Erik ten Hag are the rumoured frontrunners to take over the Molineux hot-seat.
