Goals in each half from Sofiane Diop and Guillermo Maripan gave Monaco a 2-0 victory away to PSG on Sunday.
The hosts came into this clash in a buoyant mood, having seen off Barcelona with a comprehensive defeat in midweek.
However, it was Monaco who drew first blood just six minutes into the fixture. A well-worked team move saw Caio Henrique send a cross-field ball to the right wing, which was headed back into the area by Ruben Aguilar.
Sofiane Diop made no mistake, with his header from six yards leaving Keylor Navas with no chance.
The visitors continued to ask all the questions in a dominant first half that saw PSG struggle to get out of the box. Navas was called into action a number of times, while the hosts did not take a shot until Idrissa Gueye's speculative effort from distance in the 40th minute.
Once again, it took just six minutes in the second half for Monaco to double their lead in a classic case of lightning striking twice.
A good ball in the area was not properly cleared by Ander Herrera. Maripan showed great awareness to control the ball, despite Herrera's touch taking it slightly behind him.
Any striker would have been proud of how Maripan found the bottom corner with a one-time finish from a stagnant position.
The introduction of Marco Veratti right after the goal helped PSG gain an upper hand in the game. However, they still struggled to get their forwards involved, with Moise Kean being the sole bright spark for the hosts.
Monaco held on for the win to ensure they completed a double over the capital side.
The win moves the Principality outfit up to 4th on the table. Here, we shall be highlighting five talking points from the fixture.
#5 Incredible title race becomes much tighter in Ligue 1
PSG are the defending champions of Ligue 1, with seven of the last eight league titles having ended up at the Parc des Princes.
The capital side came into this season as odds-on favorites to retain their title, owing to the vast superiority of their squad compared to the rest of the competition.
However, it has been less than a smooth sail for Les Parisiens. They were seeking to close the gap on table-toppers Lille with a win against Monaco.
Instead, PSG fluffed their lines, which means that they are now four points off the summit with just 12 games left in the season.
Furthermore, Monaco reinstalled themselves in the title race with this victory, as they currently sit directly beneath PSG in 4th spot, six points behind Lille.
Second-placed Lyon complete the quartet of teams with a stake in the title race this season, and the Ligue 1 battle is sure to go down to the wire.
This is a far cry from previous seasons where PSG would have effectively wrapped up proceedings by now.
Like in most other mainstream leagues, fixture congestion and injuries owing to the COVID-19 pandemic have altered the dynamics at the top, making things a whole lot more interesting.
#4 Monaco register first double over PSG in a decade
When the sides met earlier in the season, PSG raced into a 2-0 lead at halftime to hold the advantage at the Stade Louis II.
This seemingly set them on their path to victory but Monaco had other ideas, with Kevin Volland and Cesc Fabregas inspiring a dramatic comeback.
This second leg victory means that Les Monégasques has won against PSG in both legs of their league fixtures this season.
The last time that happened was in the 2009-2010 season when a 2-0 home win on matchday five was followed by a 1-0 win at the Parc des Princes on matchday 21.
#3 Compact Monaco keep PSG at bay
Considering that PSG scored four goals away to Barcelona just five days ago, Monaco had their work cut out if they were to leave the capital with anything.
Despite the daunting size of the task before them, the visitors held firm and put in one of their most comprehensive performances of the season.
Niko Kovac set his side up to limit the effectiveness of the PSG midfield, with major emphasis placed on maintaining their shape at all points. Aurelien Tchouameni and the ubiquitous Youssouf Fofana also won the midfield battle against Ander Herrera and Idrissa Gueye.
This concordantly meant that Kylian Mbappe and Mauro Icardi were starved of service, with the PSG number nine having just 15 touches - the least of all 22 players that started the game.
In total, the hosts had just one shot on target, which is rather surprising, considering the abundance of attacking talent they had in their ranks.
For a side that struggles defensively like Monaco, it was no small feat keeping PSG quiet on their own turf. This further highlights how impressive the visitors were on the night.
#2 Impressive Maripan shows his abilities at both ends
Guillermo Maripan scored the all-important goal that gave Monaco a two-goal cushion. Prior to that, the 26-year-old had been a rock at the back, thwarting the few attacks that PSG managed to launch.
The Chile international made six clearances on the night and won three tackles, with his defensive solidity helping Monaco keep a rare clean sheet.
He also came to the fore at the other end, where his world-class finish highlighted his confidence in his abilities.
Incredibly, this was Maripan's 5th league goal of the season from just 13 starts. Niko Kovac will be hoping his defensive stalwart continues to churn out performances like this.
#1 No heroics for Kylian Mbappe against former side
Kylian Mbappe burst into world consciousness with Monaco and has since gone on to recreate history with the French national team and PSG.
His latest jaw-dropping performance came at Camp Nou, where he was the mastermind behind Barcelona's 4-1 whitewash with a stunning hat-trick. It was on the back of this performance that the 22-year-old faced his former side.
Monaco would have been wary of the threat posed by Mbappe. However, a resolute performance ensured that the World Cup winner did not have too much of an impact.
Mbappe failed to register a single shot in the game, while he was forced to drop back into midfield to try and influence proceedings.
It was generally a frustrating night for the PSG number 7. His exasperation got the better of him in injury time when he was booked for a cynical challenge on Axel Disasi.