Real Madrid 4-2 Bayern Munich: Los Blancos' controversial step towards greatness in 2016/17

For Real Madrid, the 2016/17 season was all about making history.

Zinedine Zidane's men were looking to become the first side to ever retain the Champions League, but when they were drawn against German giants Bayern Munich in the quarter-final of the competition, the realisation as to why nobody had ever won back-to-back titles became clear.

In the first leg, Real were largely outplayed but were dragged to victory by Cristiano Ronaldo, who bagged two second-half goals and baited Javi Martinez into two yellow cards to fire Real to a surprising 2-1 win.

It wasn't pretty, but at least there was no controversy about it. This was just Ronaldo doing Ronaldo things. Bayern, who had deserved the victory, weren't the first team to come up short to him and they wouldn't be the last.

However, the second leg was full of drama and controversy.

Things started off at an electric tempo. Both sides had numerous chances cleared off the line, but first blood went to Bayern just after the break when Robert Lewandowski stepped up to convert a penalty. Game on.

From that point on, Real seemed to lose their heads. They could not get a grip on the game as Bayern pushed and pushed and pushed for the second goal needed to guarantee them a spot in the semi-final.

Arturo Vidal spurned a fantastic opportunity to get that goal, and his profligacy was punished in the 75th minute as Ronaldo (of course) popped up out of nowhere to head home a Casemiro cross and give Real the advantage they did not really deserve.

The nervy nature of Real's performance was obvious, and just 36 seconds after Ronaldo's header, it was nearly fatal. Los Blancos were all shook up at the back and a major miscommunication saw Sergio Ramos slot the ball into his own net with the kind of precision that would have made him a hero had it been at the other end.

Keylor Navas and Nacho Fernandez both expected to get the ball themselves, and all three were left with egg on their faces as Bayern celebrated the fact they were heading to extra time.

It had been scrappy up to this point, but in the 84th minute, it started to get messy.

Marco Asensio came charging down the left wing and was expertly dispossessed by Vidal, whose clean challenge was obvious to everyone apart from the referee. The Chilean was booked, and because he had already seen yellow earlier in the game, he was gone. A clean challenge had left Bayern in the lurch.

"In a quarter-final you have to put a better referee, or it is the moment to introduce video refereeing, which is what UEFA are trying, because there are too many errors," Bayern manager Carlo Ancelotti said (via BBC Sport) after the game.

Despite their disadvantage, Bayern held firm in extra time, but their spirits were broken by Ronaldo yet again. He fired home his 100th Champions League goal in the 105th minute - Madrid neighbours Atletico reached 100 as a club on the same night - but the problem was he was clearly offside when he got the ball.

Two enormous decisions had gone against Bayern, and the Germans collapsed after that. Ronaldo completed his hat-trick after the interval and Asensio bagged a fourth to make this tie look far more comfortable than it was.

Real would go on to beat Atletico in the semis and Juventus in the final, sealing their spot in history as the first side to win back-to-back Champions Leagues, but whether they should have had the chance to get that far is up for debate.

It was this game that created the 'Real paid the refs' narrative that dominated Twitter for a good few years. Everything that could have gone against Bayern, did.

Real undoubtedly rode more than their fair share of luck in this tie, but sometimes all you need is the greatest goalscorer in the history of football to guide you through.

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