Brentford struck at the death to grab a point against London rivals Chelsea, who were far from their best in this encounter.
Maresca rested some key players ahead of the club's Champions League fixture midweek, but still fielded a strong squad that was expected to win.
But Brentford defied these odds and took the lead through Kevin Schade. The Blues fought back and took the lead in proceedings thanks to goals from the returning Cole Palmer and Moises Caicedo.
However, Brentford would refuse to lose this one as an injury-time goal from Fabio Carvalho ensured that the Bees would leave with a point.
Story of the Match
It's fair to say that it was quite a scrappy start to the first half for both sides as they tussled over the control of the match.
Neither side was able to generate any clear-cut chances in the opening stages of the encounter, but Brentford were certainly the team getting into the more dangerous areas.
Chelsea - with a rotated team ahead of their Champions League clash with Bayern Munich on Tuesday - were slow off the mark and were struggling to threaten Brentford's defence.
The Bees showed intent early, clearly displaying that they were not afraid to attack their opponents' backline, which was without its usual full-backs and therefore more disorganised than usual.
Brentford had come into this game with a clear game plan to get behind Chelsea, going one-on-one with one of their centre-backs, as the other has a tendency to step up and leave that space.
They executed this plan perfectly in the opening 45 minutes and got their reward for their efforts. Jordan Henderson played a stunning pass through to Kevin Schade, leaving just Tosin Adarabioyo between him and Robert Sanchez.
The German cut in and pulled the trigger. With the help of a deflection off the leg of Tosin, the shot caught out Sanchez and flew into the bottom corner to give Brentford the lead.
It was the same old story for the Blues, who had struggled once again against a low-block and had been punished for it, entering the break a goal behind.
Chelsea had made four of their substitutions ten minutes into the second half as they brought some more of the first-team players, such as Marc Cucurella, Reece James, and the returning Cole Palmer.
The latter provided an instant impact. Joao Pedro headed the ball down for Palmer, who hit his shot first time past a rooted Caoimhin Kelleher - Chelsea were suddenly back in this contest.
This also ended Palmer's Premier League goal drought, scoring for the first time in the league since January 14th against Bournemouth.
There was an instant momentum shift following Palmer's finish as Chelsea now looked the team more likely to grab a winner. However, Brentford would not go down without a fight, still creating threatening opportunities, primarily from long throws, which Chelsea were struggling with.
Palmer had a golden chance to find the back of the net in the 75th minute. The Englishman burst into the box and got on the end of the ball played in by Pedro Neto. It looked like a guaranteed goal, but Kelleher got down to make the save and keep the encounter level.
But this looked like an issue of the past, as ten minutes later, the ball broke to Moises Caicedo, who unleashed a venomous strike that flew into the back of the net to seemingly win the game for his side.
Chelsea just had to hang on for what remained of the game plus stoppage time, but Brentford were not going down without a fight as they continued to threaten an equaliser.
In the 93rd minute, Chelsea's defence caved and Brentford grabbed a point at the death. The long throws that the Blues had struggled with all game were their downfall, travelling through to an unmarked Fabio Carvalho, who fired his effort past Sanchez.
It was a disappointing end to the game for Chelsea, who would feel more like they lost two points than gained one. They will be looking to put this one behind them quickly ahead of their clash with Bayern Munich on Tuesday.
Keith Andrews and Brentford, on the other hand, will be thrilled with this point. It was easily the Bees' best performance of the season as they will be looking to build on this in the coming weeks.
Player of the Match: Michael Kayode
The Italian was a nightmare for the Blues to try and handle. He progressed forward with every chance he got and caused Chelsea's frail backline a lot of issues.
The wing-back completed the most dribbles of any player in the match (3) and won 75% of all his duels.
Whilst he committed to attacking a lot, he was also impressive defensively, allowing Jamie Gittens very little space to operate whilst he was on the pitch.
It was a fantastic performance from Kayode, who continues to flourish for the Bees.