In 1999, Xavi Hernandez was named as La Liga's breakthrough player of the year. Little over a year later a skinny 16-year-old called Andres Iniesta turned up, in a somewhat bewildered state, for a training session with the FC Barcelona first team.
In what has now become a famous quotation, Josep Guardiola turned to his then colleague Xavi and said "You're going to retire me. This lad is going to retire us all."
Now, Guardiola doesn't get many things wrong, but while he was overwhelmingly right in his assessment of the young Iniesta, he may have jumped the gun with his—albeit tongue in cheek, no doubt—suggestion that Xavi would be forced into retirement.
12 years later and there is not a competition—in club and international football—that the two of them have not won. A World Cup and European Championships with Spain are lined with Champions League and La Liga triumphs with Barcelona.
Both see themselves as occupying the No.8 shirt so they have an agreement; Xavi would have it for La Roja, Iniesta would occupy it at La Blaugrana.
But is it possible to differentiate between the two in terms of their importance to their club side?
Xavi just ticked into his 34th year and through the emergence of Barcelona's unique style over the last seven years, there is not one player that represents tiki-taka better than him.
Even this season, Xavi is still the catalyst for Barcelona's passing game. He averages 109.1 passes every match with a pass completion rate of just over 95 percent—in the Champions League he's been averaging nearly 150 passes in each game (via whoscored.com).
His contribution in the final third has never been noted as his strongest asset, but this season he continues to weigh in with his fair share of goals and assists. Five goals and seven assists were racked up before his recent injury halted him from more.
While Iniesta fits in to the same style, he plays with a bit more emphasis on providing the transitions between the possession in midfield and attacking moves in the final third.
Always finding space and creating chances with his eye for a wonderful pass and his fabulous footwork, he has found himself used mainly as a left forward this season—although a few would be willing to argue that he looks more dangerous when shifted centrally.
Despite playing wide, the 28-year-old has set up 13 goals this season and scored five. His passing stats don't rival Xavi—he averages 80 a game—but with over 91 percent of them completed he rarely gives the ball away.
There is no doubt that Xavi has been the key cog in the development of Barca's style and success and he continues to be one of the main players in any Barcelona XI which steps out to play.
However, with that style coming under attack in recent weeks, it is the transitions that Iniesta offers which will prove more decisive to Barcelona in the coming months—no more so than on Tuesday night when they'll need to score at least three times if they want to progress without penalties against AC Milan.
One thing is for sure though, La Blaugrana are a much stronger side with them both involved.
Who do you think is more important to Barcelona? Or is it impossible to differentiate the two?