The 2016/17 season came to a conclusion with Los Blancos lifting the UEFA Champions League trophy, becoming the first team to defend the modern Champions League title. The team has won thrice in the last four years, and most of the players on this squad have cemented their name in footballing history.
But, the champions have started the new season in quite a meek fashion.
At fourth position, they trail the table toppers, and fierce rivals FC Barcelona by eight points, in La Liga. And they have conceded the top spot in their Champions League group to a team that is placed sixth in the Premier League - Tottenham Hotspur.
This misfortune has been attributed to their misfiring star forward Cristiano Ronaldo, to an injured Gareth Bale and to a lack of passion in general. The fact remains, that most of the key players are ageing and Madrid seem destined for a mediocre season.
Meanwhile, with summer signings, squad revamps and new strategies, many teams in Europe have started their respective seasons in astounding fashion, and will have their eyes set on Ol' Big Ears.
Many top teams from different parts of Europe are in contention and the Spanish hegemony over the trophy might end soon. That being said, here are 5 teams that stand the best chance of knocking Real Madrid off of their perch in the future:
#5 Manchester United
The Red Devils have not had a bad start to the season, but it would have definitely looked like a better one, if their noisy neighbours had not been in stunning form. They sit atop their UEFA Champions League group with ease, and are second in the league to Pep Guardiola's unstoppable side.
Majority of the points dropped by Mourinho's men have come in Paul Pogba's absence, and his return from the hamstring injury has bolstered the squad. In David De Gea, United have the best goalkeeper, if not the best player of recent times.
The midfield is packed with talent. In the middle of the park, United boast the right mix of defensive and attacking ability. At Old Trafford, Jose Mourinho does not enjoy the pleasure of world-class defenders, that he enjoyed in his previous Champions League campaigns.
But it was the 'Special One' that made them world-class rather than the other way round. Also, Romelu Lukaku, as the spearhead of the attack is a worrying prospect, which will prove problematic in important games and clutch situations.
But in Jose Mourinho, the Red Devils have a manager famous for his ability to outthink his rival in big games and churn out desired results in big matches against better opponents. With a few moments of magic and brilliant individual performances, they stand a good chance of lifting the trophy for the first time since 2008.
#4 Bayern Munich
Bayern Munich didn't start the Bundesliga in their usual stellar fashion. Following a 3-0 defeat at the hands of Paris Saint-Germain, their manager Carlo Ancelotti was sacked. Bayern had started as a favorite for the European title, given their bench strength and how they were unfortunate to not progress in their previous campaign.
Ancelotti was replaced with fan-favourite Jupp Heynckes. And in his second stint, Heynckes has quickly breathed fire into the team's season. The Bavarians are back to where they belong - on top of the Bundesliga table, although that is no standard to measure their chances in Europe.
Bayern's bench strength is incredible. Their move for James Rodriguez has paid dividends and Joshua Kimmich has finally reached his potential. In Robert Lewandowski, they have one of Europe's most feared strikers and he is yet to have a big European night since he netted four goals against Real Madrid with Borussia Dortmund. This could be his year.
The big setback though, is the absence of ace goalkeeper Manuel Neuer, but he is set to return to the side in January. They will be hoping he takes up from where he left off. With immense talent all around the pitch, Bayern Munich can never be written off. We all know what happened the last time Heynckes had the reigns at Allianz Arena.
#3 Barcelona
The Catalonians are through to the Champions League's round of 16, as group winners. They also top La Liga, five points ahead of second-placed Valencia. This isn't a fair depiction of their form though, as most of Barca's wins have not been comprehensive and their biggest rivals are having a meltdown.
This is not the trademark Barcelona, but neither is this the blunt Barcelona of last season. Ernesto Valverde has revived the side and they already have one hand on the league title. The Champions League, however, is a more daunting challenge and Valverde's inexperience will be put to test on the big stage.
He has shifted Barcelona's style of play from the naive direct football Enrique was trying to use. In this venture, he has used Neymar's departure as an opportunity, which has prompted both, Lionel Messi and Ivan Rakitic to state how the Brazilian's move to Paris Saint-Germain has come as a boon.
He has made the midfield more compact and the defence, impenetrable. The manager has made it clear that the team's game will be centred around the best player of this generation; which is only obvious.
But this overdependency could backfire in important knockout matches, where Messi could be injured or marked out of the game.The victim of this shift of strategy, however, is Luis Suarez, who looks like a shadow of his former free-scoring self.
The odds are only going to increase, with Ousmane Dembele's return by Christmas and an easy La Liga campaign. And with the G.O.A.T. in your lineup, nothing is really impossible.
#2 Manchester City
Fourteen wins and a draw, in the hardest league in the world. The best start ever, to a Premier League campaign. Pep Guardiola is making a mockery out of the Premier League and his team is playing an exquisite brand of football while doing the same.
They have also topped their UEFA Champions League group with ease, winning all their games. All their summer signings are proving to be bargains and they are winning effortlessly. All records are on the verge of being broken, if they haven't been broken already.
Guardiola has not just transformed the way his side plays; he has transformed his players too. Nicolas Otamendi looks like a beast. De Bruyne is channelising his potential to become the best midfielder in the world.
In Ederson, he has finally found the composed ball-playing goalkeeper he has always wanted. He has even helped Raheem Sterling change from a show-pony to a match winner. The former Barcelona and Bayern Munich manager sure is working wonders at the Etihad.
They have lost only two points and it's already December. No team has found a weak spot, a way to defeat Machester City. And yet, they are not placed first on this list, because the UEFA Champions League is not just about talent.
It's about nerves as much as it's about talent. The Citizens do not have an experienced go-to player, for the bigger stages of the tournament. And that could prove to be what decides it all, in the end.
#1 Paris Saint-Germain
The sheer firepower. The amazing bench strength. The excellent balance all around the pitch. Paris St. Germain has everything European champions need. They are nine points ahead of second-placed Olympique Lyon, in Ligue One, which is not that big a deal.
But you're considered a real contender when you defeat a formidable side like Bayern Munich, in a comprehensive 3-0 victory.
Their attacking trio looks unstoppable. Edinson Cavani has netted 17 goals in the league and 6 in the Champions League. Neymar seems all set to break the Messi-Ronaldo hegemony over the Ballon d'Or with brilliant performances for the Parisians, day in day out.
He has a mind-blowing average rating of 9.04 on WhoScored. It says something about the three-man attack, when Kylian Mbappe, with 8 goals and 7 assists, in both competitions combined, is the weak link.
Adrien Rabiot has been a revelation and his midfield partner Marco Verratti is in his usual stunning form. Thiago Silva and compatriot Marquinhos have been solid at the back, allowing Layvin Kurzawa and Dani Alves to flourish.
Among all these brilliant individuals, Alphonse Areola and Julian Draxler have often been overlooked, despite having been in good form themselves.
On paper, they are the strongest side in Europe. The one big reason they were knocked out in their last campaign, was Neymar. And they have bought him for €222 million.
In him, they have a go-to man who has lifted the trophy before, and has the magic to turn a game on its head. Unai Emery's men look all set to bring the holy grail of European Football to Paris for the first time in history.