Unai Emery's side looked to be cruising to all three points courtesy of goals either side of half time from Edinson Cavani and Neymar, but they failed to put the game to bed despite creating a plethora of gilt-edged chances.
Monaco threatened to make them pay for their profligacy when Joao Moutinho's free kick deflected off the returning Kylian Mbappe and in nine minutes from time, but PSG held on to come away with all three points.
Find out how all of the action from an eventful contest unfolded courtesy of Sports Mole's minute-by-minute coverage below.
The champions currently trail PSG by six points and know that defeat tonight could spell the end of their title hopes after just 14 games of the season, with the free-spending capital outfit in scintillating form at the moment.
It promises to be a thrilling contest between two high-scoring sides, but before we take a closer look let's first check out the team news...
Well, starting with the hosts they have seemingly resisted the temptation to mimic PSG's 4-3-3 formation, instead choosing to stick with what looks like a 4-5-1 system this evening which will see the in-form Radamel Falcao lead the line alone.
The Colombian international has found the back of the net 13 times in just 10 Ligue 1 appearances so far this term, while in all competitions his scoring rate is also impressive at 16 goals in 17 outings. He will likely be Monaco's main dangerman this evening.
Last season they had the likes of Mbappe, Bernardo Silva and a fully fit Thomas Lemar around him in the final third of the pitch, but this season the next highest scorers for Monaco in Ligue 1 have been Traore and Keita, both of whom have only three goals apiece. Keita starts this evening, but Monaco need more goals from elsewhere if they are to catch the leaders.
Almamy Toure also returns to the fold for Monaco and could feature in a wing-back role tonight should Monaco opt to play three at the back rather than a 4-4-2 system.
That means starts again for the front three of Neymar, Cavani and Mbappe, the latter of whom returns to the Stade Louis II for the first time since leaving the club during the summer on an initial loan deal which will turn into a £166m permanent move at the end of the season.
The Uruguayan striker has scored a phenomenal 23 goals in just 21 games across all competitions this season, while in Ligue 1 alone he has 15 goals and two assists in 12 outings.
Mbappe, meanwhile, has scored seven goals and provided seven assists in 13 appearances for the club, four of which on each count have come in Ligue 1.
the defence of Alves, Silva, Marquinhos and Kurzawa has a distinctly Brazilian feel to it, and there is plenty more flair in midfield too.
The reigning champions already find themselves six points adrift of PSG at the top of the Ligue 1 table, and another defeat this evening would see that gap grow to nine - which could well be unassailable considering PSG's brilliant form.
Only leaders PSG have scored more that the Principality's 35 from 13 games, while just two teams have conceded fewer too.
Leonardo Jardim's side fell to a 4-1 home loss at the hands of RB Leipzig on Tuesday, ensuring that last season's semi-finalists will finish bottom of Group G. Many would have made Monaco favourites to win that group too as they were up against Leipzig, Besiktas and Porto, but they have picked up only two points from the 15 on offer.
However, they are unbeaten in their last four Ligue 1 outings, including three wins and three clean sheets, with the only exception coming in their most recent league match when they were held by surprise package Amiens.
At home Monaco are now unbeaten in their last 16 Ligue 1 outings, including all 15 so far this calendar year, with just one draw in that time and the rest victories.
One thing we should be guaranteed tonight is goals, though. Monaco have not failed to score in a home league game since PSG's last win here in August 2015, finding the back of the net in all 42 matches since. Indeed, they have scored two or more goals in 15 of their ongoing 16-match home league unbeaten streak.
Indeed, home and away Monaco have picked up the same number of points in their opening 13 games this term as they did on their way to the title last season, although this time around they have much stiffer competition.
Unai Emery's side have dropped just four points in the league all terms, building a six-point lead over Monaco in the process which they could extend even further tonight.
The Parisiens' unbeaten run now stands at 23 games stretching back to last term, with 20 wins in that time since a 3-1 defeat to Nice in April.
Indeed, PSG have scored 24 goals during those five games at a staggering average of 4.8 per game, while in all competitions they have found the back of the net 69 times in 19 outings this season, still yielding a healthy average of 3.6 per game.
It will not come as a huge revelation that PSG boast the best attack in Ligue 1 this season with 43 goals from only 13 games, and they have also kept things relatively tight at the other end with only Montpellier having conceded fewer.
Despite their perfect record PSG are not quite guaranteed top spot in Group B yet, but they would need to fall to a heavy defeat at the hands of Bayern Munich on the final matchday to let it slip from this position.
It would not be fair to suggest that the capital outfit are week on the road, though - they are unbeaten in their last nine away games across all competitions and have scored three or more goals in five of their eight trips so far this season, after all.
Only Monaco can match PSG's away points haul so far this season, although the Parisiens have played a game fewer yet still managed to score the most goals (17).
Against any other team in Ligue 1 most would automatically back a PSG win here, but Monaco are so strong at home - at least domestically - and always seem to raise their game when playing PSG. There should hopefully be goals between the divisions two best attacking outfits, but I think they could cancel each other out.
SPORTS MOLE SAYS: Monaco 2-2 PSG
The most recent was a come-from behind 2-1 win for PSG in the Trophee des Champions - the French Super Cup to you and me - at the start of this season, when Alves and Rabiot scored in the second half to cancel out Sidibe's opener.
Monaco are unbeaten in their last three Ligue 1 clashes with PSG stretching back to a 3-0 defeat at home in August 2015, with their most recent contest ending 1-1 in January when Bernardo Silva scored in the 92nd minute after Cavani had given PSG the lead nine minutes from time.
That may not sound like the most impressive record on the face of it, but considering they have lost just once in that time, with nine draws, it is safe to say that Monaco have had the better of this fixture in the league over the past decade.
MONACO STARTING XI: Subasic; Glik, Jemerson, Raggi; Touré, Fabinho, Moutinho, Tielemans, Jorge; Falcao, Keita Balde
PSG STARTING XI: Areola; Alves, Marquinhos, Silva, Kurzawa; Verratti, Rabiot, Draxler; Mbappe, Cavani, Neymar
The Uruguayan doesn't need a helping hand to score, but he gets one from the hosts here as first Monaco give the ball away inside their own half and then fail to deal with the danger. Rabiot slips a pass into the box for Draxler, who in turn is allowed to squeeze a cross into the box. Cavani has somehow been left unmarked inside the six-yard box, and he applies a really smart finish to clip the ball into the roof of the net.
Edinson Cavani for PSG across all competitions since the start of last season:
🔵 69 games
⚽️ 71 goals
El Matador is on fire on BT Sport 1 HD 🔥 pic.twitter.com/SZ3rua615O— BT Sport Football (@btsportfootball) November 26, 2017
The visitors have not completely dominated, but they have created all of the best chances and should be at least two goals to the good. It could comfortably be three or four for PSG at the interval, though.
The hosts lost the ball inside their own half and then failed to close down both Rabiot and Draxler as they combined to set up Cavani. The worst part of the defending was leaving the deadly Cavani unmarked inside the penalty area, though, and he made no mistake with a smart finish from close range.
Mbappe beat Subasic to the ball and stayed on his feet while rounding the keeper, but with the goal gaping he could only find the side-netting against his former club.
Alves had played the ball through for Mbappe down the right channel, and he in turn pulled it back for Cavani inside the box. Cavani was unable to turn his flick on target, but he did steer it into the path of Draxler, who was caught on his heels a little.
Neymar himself won the penalty after getting in behind Toure and then slowing down to make the defender clumsily bundle in to him. He played for it, but Toure fell for it and the referee had no hesitation before pointing to the spot.
Monaco win a free kick right on the edge of the area and Moutinho's effort is not particularly good, but Mbappe ducks when trying to avoid it and the ball loops off his back and in. It will go down as Moutinho's goal, and suddenly Monaco will be thinking about stealing a point from this match.
The usual suspects of Cavani and Neymar got on the scoresheet for PSG, but they missed a string of glorious chances to wrap the game up and eventually had to hang on for the win after Moutinho's free kick deflected in off Mbappe.
Thank you very much for joining Sports Mole for tonight's match as PSG hang on to move nine points clear at the top of the Ligue 1 table courtesy of a 2-1 victory over Monaco. I will leave you with our match report, but from me it is goodbye for now!