Riyad Mahrez's free-kick 19 minutes from time took Manchester City within touching distance of a first ever Champions League final as they came from behind to beat Paris Saint-Germain 2-1 at the Parc des Princes on Wednesday.
PSG captain Marquinhos headed the hosts into an early lead, but City composed themselves after half-time to take a firm grip of the tie.
Kevin De Bruyne's cross found its way into the far corner for a vital away goal to level before Mahrez's strike found a hole in the Parisian wall.
Here, AFP Sport looks at three talking points from a thrilling first leg:
City learn their lesson
Pep Guardiola's five seasons in Manchester have been filled with domestic trophies and Champions League collapses.
This is the first time the English champions-elect have even reached the last four under the Catalan coach, but they showed a new maturity on the European stage to ride out the early Paris storm.
City's previous Champions League exits have been characterised by conceding multiple goals in quick succession.
Despite the early blow of Marquinhos's towering header, the visitors kept their composure to get to half-time just a goal behind.
Guardiola's men found their groove after the break, but this time they were the beneficiaries of two defensive mistakes to take control of the tie.
Firstly, Keylor Navas misjudged the flight of De Bruyne's cross that nestled in the far corner before Mahrez's free-kick flew through a gaping hole in the PSG wall.
Mbappe and Neymar nullified
PSG's star duo Neymar and Kylian Mbappe were too hot for reigning champions Bayern Munich to handle in a thrilling quarter-final, but City showed why they have the best defensive record in the Champions League this season.
Neymar threatened to spark into life early on as his quick footwork teased the City defence, but the centre-back partnership of Ruben Dias and John Stones that has carried Guardiola's men to the brink of the Premier League title stood firm.
Only once did Mbappe's pace leave Stones for dead, but Marco Verratti just failed to connect with the French international's teasing low cross with the chance to double PSG's lead early in the second half.
There remains plenty for City to do in next week's second leg, but PSG will need much more magic from the world's two most expensive ever players if they are to reach a second consecutive Champions League final.
Mahrez makes his mark on homecoming
The Algerian grew up on the Parisian suburb of Sarcelles, but has taken a long and winding road back to scoring the winner of a Champions League semi-final in his home city.
Mahrez was not a star of one of France's vaunted youth academies and made his way to English football with Leicester from Ligue 2 side Le Havre.
A star of the Foxes' stunning Premier League triumph in 2015/16, he eventually got his big move in 2018.
Despite costing a then club record £60 million ($83 million), Mahrez was only a bit-part player in City's domestic treble triumph in his debut season.
But he has come of age as a City player this season, becoming one of the first names on Guardiola's teamsheet, while the likes of Raheem Sterling, Sergio Aguero and Gabriel Jesus have had to settle for a place on the bench.
All eyes were on De Bruyne when City were awarded a free-kick in a perfect position.
But the Belgian's confidence in stepping aside for Mahrez proved the right call as his left-footed effort gave City a priceless lead in the battle between two clubs with seemingly bottomless pits of cash to throw at winning this competition for the first time.