During the entirety of 2014, spanning some six matches, Barcelona failed to break down Atletico Madrid and get a win against Diego Simeone's side.
It would, ultimately, come back to haunt them on the final day, with Diego Godin's leveller winning Atleti the title at Barca's Camp Nou in a winner-take-all 90 minutes. Fast forward to January 2015 and the roles have been reversed. Two games played, two Barca wins.
Both victories have certainly not been fortuitous either, with the first meeting defined by a comprehensive all-round performance from the Blaugrana.
If Simeone expected things to even themselves out, he's barking up the wrong tree. Barca are back to their best at present. Persistent, hungry and sharp, since the beginning of the New Year, we have seen the Barca of yore. And it doesn't get any better for the Rojiblancos as the Catalans will triumph in the Vicente Calderon.
Here are three reasons why
Away goal crucial
Despite only securing a narrow single-goal win in the first leg, keeping Atleti at bay in front of goal was crucial for Barca's chances of progression.
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The Catalans are perfectly capable of plundering an away goal themselves given current form and the likelihood that Atleti will then score three, as they will have to do to progress, is miniscule. They haven't scored three against Barca since 2009, a 4-3 epic at the Calderon.
Diego Simeone will ask his players to dig deep as usual, but the 1-0 rather than say a 2-1, is an infinitely better result for Barca.
The best defender in La Liga, perhaps in Europe, will not be playing in the second leg, to give another huge boost to the away side. Atleti had seen out the 90 minutes without any of the players already on a yellow card getting booked.
That all changed during injury time as a needless kick out by Diego Godin was noted by the ref and a yellow immediately flashed. Atleti aren't quite the same proposition without their captain in-situ and Godin's stupidity has almost certainly cost his side the chance of progression as the Catalans seek to benefit from a make-do-and-mend back line.
Calderon holds no fears
Although Barca failed to beat Atleti in 2014, it should be noted that only once in the last five years have the home side taken all three points at the Vicente Calderon.
The pressure is therefore all on Simeone's men to deliver. Whilst not their natural game, Barca can afford to sit back and play a typical away side counter-attacking game.
Or take the game to Atleti and get that quick early goal. Whether or not the Vicente Calderon provide an intimidating atmosphere, Barca are in the box seat.