Real Madrid look a sure bet to progress to the Champions League semi-final after recording a 3-0 victory over Juventus in the first leg. However, as Barcelona showed the footballing world on Tuesday night, nothing can be taken for granted in Europe.
Supporters of 'Los Cules' are still reeling from their Olympic Stadium nightmare which saw a three-goal deficit be overturned by Roma as their dreams of a treble fell by the waist-side.
It means that another year goes by without a highly-anticipated 'Clasico' showdown between Madrid and Barca in the final of Europe's premier club competition.
It's unpredictability has already shocked us all and the Catalan giants are the perfect example of how league form doesn't necessarily translate into the Champions League, whereas their Spanish rivals are the opposite.
A disappointing La Liga campaign has been cancelled out by an impressive run in the continent, one that has already seen Zinedine Zidane's men knock out runaway Ligue 1 leaders Paris Saint-Germain.
However, Madrid cannot take their three-goal lead over Juventus for granted. There is still 90 minutes to go and it only takes one goal to spark a comeback.
Their opponents will be boosted by the return of Miralem Pjanic from suspension, while Gianluigi Buffon, Gonzalo Higuain and Sami Khedira will be hoping to put right the mistakes from the first.
On the other side of the pitch, 'Los Blancos' will be without captain Sergio Ramos, suspended after picking up another booking in Turin, while Nacho remains sidelined.
The Serie A outfit has never scored more than two goals at the Bernabeu, which they will have to change if they are to progress to the semi-finals. But if they can follow Roma's approach and get an early goal, anything is possible in Europe.