The masters of the premier European competition and the relative new boys in town in terms of UCL wins had played each other in last season's play-offs, in the 2023/24 quarter-finals, the 2022/23 and 2021/22 semi-finals and also the 2019/20 Round of 16.
No Mbappe for Real
Before that run of games, they'd met each other only twice, in the 2015/16 semi-finals and the 2012/13 group stage.
Ahead of Wednesday night's game, the balance of results was just in Los Blancos' favour, with five wins to City's four, and five draws.
Oddly enough, for two of the more successful teams in Europe, City's 16 points in the league phase of this season's competition meant that they just scraped through to the knockout stages automatically.
Real's ninth-place finish on 15 points meant they needed to overcome Benfica - the team whose last-gasp victory knocked them out of the top eight - in the play-offs.
Their four wins and one loss at home in this season's competition would surely mean they would be the toughest of opponents for the Premier League side, even without the injured Kylian Mbappe, though Pep Guardiola's side headed into the match on the back of a four-match away unbeaten streak.
Route one from Los Blancos
The opening exchanges, as might be expected, were relatively equal, as Madrid fired off three attempts at goal and City two of their own in the first 18 minutes.
Signs were already there as to how easily the away side's defence could be opened up, and City were completely undone when Thibaut Courtois' route one clearance found Fede Valverde.
Real's captain still had much to do, but a delicious first touch took him well clear of Nico O'Reilly, before a deft touch saw him round Gianluigi Donnarumma and score into an empty net.
Ironically, that goal was his first in the Champions League since April 9, 2024 - against Man City.
Valverde 2 City 0
It would also be one of only four touches he'd have in City's box in the entire 90 minutes, and as the game unfolded, the Uruguayan would stamp his authority all over this fixture.
Just seven minutes later, he doubled Real's lead with a superbly taken left-foot shot that owed much to City's inability to get anywhere near Brahim Diaz and Vinicius Junior, as they made their way up the pitch.
Both Ruben Dias and Marc Guehi made just one attempt at a tackle each in the entire game, losing out on both occasions, and one interception between them across the 90 minutes speaks volumes as to the standard of their defending.
Though they did make eight of City's 10 total clearances in the game, that's as much to do with pushing the panic button as anything else, for the pair were not at the races for long periods of the match.
Haaland off the pace
Attacking-wise was no different for the visitors, with Erling Haaland having no shots whatsoever, just nine touches in total in the first half, and only one touch in Real's box before he was hauled off.
Of all of City's front men, only Antoine Semenyo offered anything approaching a decent standard of work, his two shots in the game both on target, and his work rate putting the more celebrated Haaland to shame.
As the first half drew to a close, Valverde had already attempted more tackles than anyone else on the pitch (four) before a superb piece of individual skill saw him get his hat-trick goal with his third shot on target in the game.
Once again, City's defence was at sixes and sevens, and that has to be a worry for Guardiola.
Vini's spot-kick regret
Even if one takes into account that four of their players attempted at least 10 one-on-one duels, the fact that only Rodri won more than half (seven from 11) is a damning indictment of their commitment in their most important game of the season.
Given that City had also had a gargantuan 75% possession in the final 15 minutes of the half, they really should've made some headway in terms of finding the net at least once during that period.
A similar theme at the start of the second half saw City with 72% collective possession, and yet they gave Vinicius the freedom of the Santiago Bernabeu to run into City's area, with only a challenge from Donnarumma stopping him, earning the Brazilian a penalty.
Vini's weak spot-kick was regrettable, as his attacking output on the night was the best on show after Valverde, and who knows if Donnarumma redeeming himself with an easy stop will be something that Real look back on after the second leg as the potential turning point in this tie.
City's UCL omen
With seven shots on target after an hour's play, the hosts remained in the ascendancy, forcing Guardiola into making more substitutions.
However, all of Rayan Cherki, Omar Marmoush and Tijjani Reijnders didn't attempt a single tackle or managed a solitary interception between them.
Jeremy Doku was at least trying to force the issue with his 16 touches in Real's box being 11 more than any other City player, albeit the winger still only managed one shot at goal, which was blocked with 13 minutes left to play.
With Real having scored in 10 of their 11 games - only Newcastle United (11) have scored more in this season's competition - it's difficult to see how City can turn this one around.
Guardiola's side have only lost one of the previous seven meetings at the Etihad Stadium, though, so they may well fancy their chances, particularly if they're able to score an early goal or two.
