Ronaldo and Real pounce to punish PSG's familiar failings
Real Madrid 3-1 Paris Saint-Germain
Real Madrid certainly wobbled but, having fallen repeatedly this season in domestic competition, they again stood tall on their favourite Champions League stage.
A sub-plot of Cristiano Ronaldo 2, Neymar 0 was also another blow for the old guard against the challenge of Paris St-Germain and was effectively the difference in a wider 3-1 scoreline.
It is only half-time in the tie though and, while Madrid's late flurry has given them a potentially crucial advantage ahead of the second leg in Paris, there was enough here from PSG to suggest that an upset remains possible.
They had earlier taken the lead and, while Neymar was fortunate to stay on the pitch following a second-half dive, they should have left Madrid with more than a solitary away goal.
There was one significant surprise in Zinedine Zidane's selection, with Gareth Bale, despite being fully fit and expected to start, left on the bench in preference for Isco up alongside Karin Benzema and Ronaldo in a three-man attack.
Bale had been hoping to join Ryan Giggs as only the second Welshman to reach 50 Champions League appearances but he could have little complaint given how Isco immediately helped pin PSG back inside their own half.
His industry off the ball was outstanding and PSG's suspect defence was forced to soak up an intense early attempt by Real to establish their seniority.
Isco was not just setting the tempo but he also created the first chance for Ronaldo, who pulled his shot across the goal.
Toni Kroos also soon forced a save from PSG goalkeeper Alphone Areola with a shot from the edge of the penalty area.
Neymar initially appeared isolated but a wonderful pass from Marco Verratti provided a first opportunity for him to run into space and while he wasted the chance, Madrid's vulnerability on the counter-attack was clear.
Neymar was then again almost released and, while he was warned over a handball and booked for a challenge on Nacho, the warning signs for Madrid were clear.
Zidane's team did still maintain their general dominance of possession and, with Sergio Ramos heading over and then Ronaldo narrowly missing with a free-kick after Isco had been fouled, neither team looked defensively secure.
This was summed up when Casemiro clumsily lost possession inside his own half to Neymar but, with Edinson Cavani completely free, PSG's world-record signing just failed to get sufficient weight on an attempted pass.
Madrid surged forward on the counter-attack and were able to release Ronaldo clear on goal, only for Areola to inadvertently block a powerful shot with his head.
PSG's threat was coming from across their front-line and they took the lead when Real goalkeeper Keylor Navas failed to collect Kylian Mbappe's cross under pressure from Neymar and the ball fell for Adrien Rabiot to calmly finish.
Cavani then soon had the chance of PSG's second away goal, but Casemiro scrambled back to make a crucial block.
The flurry of PSG pressure seemed also to provoke more urgency in Madrid.
First Ronaldo squandered a second clear sight of goal by shooting over and then Karim Benzema forced a brilliant diving save from Areola.
Real played the ball short from the resulting corner, with Kroos drawing a challenge from Giovani Lo Celso that prompted no hesitation in referee Gianluca Rocchi's award of a penalty.
Ronaldo stepped up and, while Areola did dive the right way, the sheer force of his shot ensured a 20th goal in his past 12 Champions League matches.
PSG began the second half with added assurance in possession and it was now Madrid being forced to soak up pressure and play on the counter-attack.
Neymar's influence was also growing and he soon identified Mbappe in space inside Madrid's penalty area but the France striker's low shot forced a wonderful save from Navas.
There was then a huge moment of controversy. Neymar was sprinting clear but went down theatrically when it appeared that he could not reach the ball.
Referee Rocchi quickly signalled that there had been no foul and appeared to be striding purposefully towards Neymar with an intent to brandish a yellow card.
Yet he then seemed to realise that Neymar had already been booked and, amid the prospect of not just ending the Brazilian's night but also ensuring that he would be suspended for the second leg, decided against any further action.
One possible mitigation was that Kroos and Luka Modric had also gone unpunished for comparable theatrics, although Rocchi may just have wished he had taken firmer action minutes later when an attempted Neymar pass smashed straight into his face.
Play had to be stopped for Rocchi to receive treatment but chances continued to be created by both teams when the game resumed.
Bale had by now replaced Benzema and soon sprinted in behind the PSG defence but, as he checked back to find support, Presnel Kimpembe recovered with a potentially goal-saving block.
PSG, though, seemed suddenly weary, perhaps as a result of how they had been forced to defend during the first half, and Madrid struck twice in four minutes.
Marco Asensio had also been introduced and he then provided two match-winning crosses. The first cannoned up off Areola for Ronaldo to score his second and then Marcelo broke in from the opposite flank to give Madrid their two-goal cushion.