A late strike by Ferland Mendy was enough to give Real Madrid a slender victory over Atalanta in the first leg of their UEFA Champions League Round-of-16 tie.
As has been the case in recent weeks, Zinedine Zidane had to travel with an extremely depleted squad to the Gewiss Stadium due to injuries. Isco was handed a rare start as the focal point of attack in the absence of Karim Benzema, while Vinicius Junior and Marco Asensio flanked him in attack.
Stand-in captain Raphael Varane made his 350th appearance for the Bernabeu outfit, and Toni Kroos also became the German with the joint-most appearances for the club.
The Real Madrid bench was less than stellar and had Mariano Diaz - himself on the fringes - as the only recognizable first-team player.
The game started on a relatively slow note, with neither side seizing the initiative, but the first talking point came in the 17th minute.
A quick break saw Ferland Mendy race through on goal before he was cynically brought down on the edge of the area by Remo Freuler. Referee Tobias Stieler wasted little time in reaching for his pocket to brandish a red card.
There were heavy protests from the Atalanta players and coaches but the decision was allowed to stand, with the VAR not intervening.
This numerical disadvantage saw the hosts withdraw into their shell, with Real Madrid dominating possession, although the Bergamo outfit still threatened to catch Los Blancos out on the counter.
The best chance of the opening 45 minutes came right on the stroke of half-time. Toni Kroos stood over a free-kick and delivered a trademark pristine cross into the area, which Casemiro attacked with a direct header at goal.
The ball, however, went straight to Pierluigi Gollini, who produced an excellent reflex save to keep the scores level.
The second half started with Real Madrid fashioning another good chance in the 47th minute. Luka Modric's shot from the edge of the area was narrowly deflected wide of the bottom post in seemingly slow motion, with everybody rooted to the spot.
The rest of the second half was relatively devoid of goalmouth action, with Real Madrid having just one shot on target until the final 10 minutes.
As time ran out, both managers made some changes in a bid to influence the game.
Luis Muriel went off for Josip Ilisic, while Mariano and youngsters Sergio Arribas and Hugo Duro all came on for Real Madrid.
Despite the changes, chances continued to come at a premium until the deadlock was broken by an unlikely source in the 86th minute.
A corner kick by Toni Kroos was not properly dealt with, allowing Mendy to rifle home a right-footed curler from 25 yards out.
A late surge by Atalanta failed to yield dividends, as Real Madrid held on for a crucial away win.
The return fixture will be played on March 16, and here are five talking points from the game.
#5 Remo Freuler's controversial red card
While the veracity of Freuler's foul on Mendy is not in doubt, questions are bound to be asked over whether it was worth a red card.
In the immediate aftermath of the foul, it was taken for granted that a yellow card would be shown. However, to the astonishment of the players and management staff, a different color was brandished.
Gian Piero Gasperini was beside himself with bemusement, and an assistant behind him seemed confident that the decision would be overturned as he gestured to the VAR with his hand.
However, the center referee's decision stood, and Atalanta had to play out the final 72 minutes of the game one man short.
The rules of the game state that a red card should be shown when a clear goalscoring opportunity has been denied. It cannot be argued that Mendy was cynically denied a goalscoring chance, but the matter of it being clear is open for debate.
A case can be made that Christian Romero beside him was in a good position to cover Mendy as he raced through on goal.
The fact that the VAR did not even deem the decision worthy of a review left a lot to be desired, and Atalanta are well within their right to feel aggrieved.
#4 Unlikely hero Ferland Mendy steps up for Real Madrid
Ferland Mendy has played a key role for Real Madrid in recent weeks, and the 25-year-old once again came to the fore against Atalanta.
Having won the foul that led to the red card for Freuler in the first half, the France international made an even bigger contribution with less than four minutes to go.
The technique shown to curl the ball beyond Gollini's dive from distance was indicative of his talent. The fact that it came from his weaker foot made it more impressive and even drew a rare smile from the normally stoic Zidane on the sideline.
Real Madrid now go into the return leg on the front foot and have their marauding left-back to thank for that.
#3 Should Casemiro have been sent off for simulation?
Casemiro's customary yellow card for a cynical challenge on Duvan Zapata in the 23rd minute means that Real Madrid will be without their midfield lynchpin for the second leg.
However, the Brazil international should arguably not have seen out the game. He had been guilty of simulation midway through the second half after coming together with Rafael Toloi.
His compatriot had barely touched him, but the Real Madrid number 14 threw himself on the ground and rolled around on the floor seeking a penalty.
Committing such acts in this age of VAR is extremely risky, and Casemiro had all the facial expressions of a naughty child who had been caught with his hands in the cookie jar.
The former Porto man was practically pleading with the referee not to show him his second yellow card for simulation, and the referee duly obliged with just a talk with the Real Madrid midfielder.
The Atalanta players were livid and rightly so, especially in light of the harsh red card shown to Freuler earlier in the game.
#2 Drab game fails to live up to expectations
Atalanta have arguably been the most exciting side in all of Europe for the last three seasons. However, they have dropped off in their intensity this term.
Real Madrid themselves have flattered to deceive and are now known more for their efficiency rather than the flair associated with them in the past.
The absence of several key attacking players has undoubtedly robbed the La Liga champions off their verve, but big things were still expected in this fixture.
It was believed that an exciting match full of goalmouth action was in store. However, both teams seemingly lined up with the intention of playing not to lose rather than trying to win.
Atalanta's early red card undoubtedly helped reduce their attacking impetus but on the overall balance of play, Gasperini's side simply did not do enough in an attacking aspect.
Rather shockingly, the hosts fashioned just two shots in the game, with none of those hitting the target. Real Madrid themselves failed to make their numerical advantage count and needed a moment of brilliance from an unlikely source to get ahead.
This was a game that promised so much but delivered so little and hopefully, the return leg will be a more enjoyable affair.
#1 Vinicius Junior's poor run of form continues
Vinicius Junior was handed a fifth consecutive start in all competitions for Real Madrid. However, he put in another sub-par performance.
The 20-year-old has been accused of stagnating in recent years and on the evidence of his display against Atalanta, those criticisms are justified.
Having been handed extra responsibility owing to several injuries to teammates, the former Flamengo man had a window of opportunity to make a mark on the biggest stage, but he fluffed his lines.
Vinicius failed to make the most of the spaces on the left of the Real Madrid attack, while his poor decision-making in the final third continuously came to the fore.
It came as no surprise that he was the first substitution made by Zidane, with Mariano coming on for him in only the 57th minute.
His blank here means that he has now gone 19 games in all competitions without finding the back of the net. At a club as demanding as Real Madrid, this is a poor return by all standards, and Vinicius Jr is running out of time to prove his worth to the club.