Athletic Bilbao’s President and former player, Josu Urrutia, almost certainly had thoughts of a revolution in mind when, during his election campaign, he backed Marcelo Bielsa to be the club’s new coach. Athletic, one of the most decorated sides in Spanish football, had just finished sixth in La Liga and two seasons earlier had reached the Copa del Rey final for the first time in 24 years.

But with a side that included two members of Spain's 2010 FIFA World Cup™-winning squad in Fernando Llorente and Javi Martinez, and bright young talents like Iker Muniain, the club seemed capable of much better. A change of direction was needed, with a coach capable of ending Athletic’s long trophy drought and restoring the club’s once powerful, successful image. An image that was in real danger of becoming a relic of the past.

The man chosen to take Athletic forward was Marcelo Bielsa, an Argentinian coach admired for his knowledge and approach to the game. Bielsa appeared to be a good fit for Athletic’s ambitions, having already worked under a similar weight of history to deliver renewed success to the Chilean national team.

Under Bielsa’s guidance, Chile put past disappointments behind them to return to the FIFA World Cup finals for the first time in 12 years, after finishing an impressive second in the South Africa 2010 preliminaries. Their progress in South Africa was eventually halted by Brazil, no less, in the Round of 16.

European revelations
Bielsa accepted the challenge, Urrutia was elected president and now, nine months later, the picture is an overwhelmingly positive one. The Argentinian has led Athletic to sixth in the league, and has guided them to May’s Copa del Rey final where, as in 2009, they will face Barcelona.

But Athletic’s change in fortunes runs much deeper. The Bilbao outfit have treated their fans with memorable displays in both domestic competitions, and have positively dazzled in the UEFA Europa League. And on Thursday, Athletic have the chance to reach a European final for the first time since their first and only appearance, 35 years ago.

Bielsa wants us to try to play like Barça.

Fernando Llorente, Athletic Bilbao forward

It is Sporting CP that stand between Bielsa’s men and a place in the final in Bucharest. To get there, however, Athletic must overturn a 2-1 deficit from the first leg, and they will be hoping for another big performance at their legendary San Mames home.

Ander Iturraspe, one of the standout performers in Bielsa’s revitalised Athletic side, said he has never been involved in “such an important match”. But he believes that, having knocked out the likes of Schalke and, most memorably, Manchester United to reach this stage, his side has gained “experience and valuable knowledge of how to get it right in these kinds of games”.

A number of brilliant displays, including the 3-2 victory over Manchester United at Old Trafford, have helped Los Leones to emerge as the revelations of European football this season. For the club’s talismanic striker Llorente, there are no doubts as to where the credit lies: “Marcelo [Bielsa] is the biggest reason why things are going so well for us. It’s amazing how much we’ve changed from one year to the next. The team’s progress has been tremendous.”

A great deal has indeed changed in the months since Bielsa took charge, perhaps most notably in the way Athletic play. Gone is their old direct, English-inspired approach, replaced by a new style that is based on possession, neat link-up play and putting their opponents under constant pressure. Sound familiar? “Bielsa wants us to try to play like Barça,” said Llorente.

Hard graft paying off
If Athletic have absorbed so many new ideas in such a short space of time, it is all down to hard work. The process began soon after Bielsa accepted then presidential candidate Urrutia’s offer, when he set about analysing the 42 matches that Athletic had played the season before. Bielsa’s meticulous approach also involved studying each squad member individually to identify their strengths and weaknesses.

And as Fernando Amorebieta explained, it is a method he still uses today. “When he thinks there’s something that you need to fix, he tells you directly, shows you a video and gets you to identify it [the problem] with the laser pointer,” said the defender, one of the most improved players under Bielsa’s command.

Bielsa’s intense training sessions also appear to be bearing fruit, with Muniain telling recently that he now finds it “easier to last the full 90 minutes in matches”. Indeed, Athletic’s displays this season have been characterised by an ability to run opponents into the ground, without offering any respite. That, and a new mentality that prompted Muniain to say that Bielsa has “transformed this side into a winning team”.

On Thursday, this new-found winning resolve will be more essential than ever. Indeed, not only does the match represent one of the biggest challenges yet for Bielsa’s rejuvenated Athletic side, it also provides them with a first opportunity to make history.