Barcelona coach Pep Guardiola might have walked away from football to take a sabbatical but as legacies go even if he decides never to manage again he will have left an indelible print on the sport.

The all-conquering Catalan coach oversaw his final game for the club on Friday, toppling Athletic Bilbao in the Spanish Cup final to take his haul of trophies to 14 during his four-year tenure.

It was a quintessential Barca performance. The game was over by the 25th minute after three goals - two from Pedro and one from Messi -- as Athletic were left chasing shadows to provide the perfect send-off for their coach.

Since taking charge of Barca in 2008, Guardiola's vision has been acted out by fellow disciples of Barcelona's famed 'La Masia' youth academy, players like influential Spanish pair Andres Iniesta and Xavi, as well as the prolific striker Lionel Messi.

They have helped Guardiola deliver three successive Spanish League titles, two European Champions League crowns, two Spanish Cups, two FIFA Club World Cup titles and five further trophies with a soulful swagger that has had many a pundit purring that this is arguably the greatest club side of all time.

"What Guardiola has done to some extent is challenge some of the truisms and clichés of football, such as defending is about sitting deep and denying space for teams," Spanish football expert Sid Lowe told CNN.

"Barcelona have done the opposite, they've gone and looked for teams, defended with possession which teams perhaps haven't done before.

"The challenge, for example, on the use of the word practical or pragmatic, to talk about what is essentially a long ball game, but what could be more pragmatic than winning what Barcelona have won in the last four years?"

Albert Ferrer played with Guardiola during a golden era for Barcelona, when legendary Dutch coach Johan Cryuff led the club to three consecutive league titles and their first European Cup triumph in the early 1990s.

Ferrer believes Guardiola's innovative, progressive approach to the game was born during that period under Cruyff , himself a staunch defender of Barcelona's cherished attacking philosophy of play.

"Pep tried to play simple football, " said Ferrer of his friend, also Catalan born and bred. "He created the philosophy where if you can play an easy pass why would you play a difficult one?

"Barcelona are one of the few teams who always had 70-75% possession in games because of the players they had and the philosophy of keeping the ball. He was very demanding of that -- not giving the ball away.

"All the teams now defend against Barcelona and he had to adapt to those solutions. He didn't always play the same system -- with three defenders or four, playing with a '9' (a traditional striker) or without a '9' -- always making things difficult for the opposition.

"All the movements he created, with the two full backs pushed forward and the center backs very wide, all started with him."

Michael Cox, from the Zonal Marking website, attributes the development of Guardiola's coaching philosophy to how the former Barca captain's own playing career panned out - where there was a general loss of faith in the deep-lying midfield position Guardiola used to occupy in favour of more aggressive midfielders

"He had to leave Barcelona as a player and take quite a big drop down to Brescia (in Italy) because, frankly, no good club wanted a player in that mould. Everyone wanted big battlers deep in midfield, like Patrick Vieira, Edgar Davids, Roy Keane, Claude Makelele.

"Now, he's managed to construct a team featuring four players who looked up to him when they were in the Barcelona youth team: Sergio Busquets, Xavi, Iniesta, Fabregas.

"I think almost every big club in Europe has copied Barcelona's way of playing, to a certain extent, in recent years. It's remarkable that that is now the way to play football, considering his struggles towards the end of his playing career as a deep-lying passer."

As ever in the often fickle world of football, Guardiola has his detractors, attributing Guardiola's success as a masterstroke of timing, claiming his tenure conveniently began just as a clutch of great players rolled off the famed Barcelona production line.

And while there may be truth in that argument, Lowe believes it was the way Guardiola allied the likes of Xavi, Iniesta, Messi, Busquets and Cesc Fabregas to embrace his football philosophy that was more pertinent.

"Guardiola has been the most zealous defender of a certain type of identity -- he hasn't been the creator of that identity," said Lowe.

"There's an almost puritanical conviction about how you've got to do things. That mindset has its flaws but Barcelona stick to it.

"He was absolutely the right man at the right time with the right squad, the right players around him. It has been a culmination of circumstance but without that identity it wouldn't have been as clear or as unshakable."

This unflinching devotion to Barcelona's cause and the all-consuming nature of the job has taken its toll on Guardiola. As well as his own meticulous nature combined with the weight of responsibility that comes with being Barca manager, another explosive element - Real Madrid manager Jose Mourinho - only added to the pressures on the 41-year-old Guardiola.

"People close to him have said they've been worried about him for a long time," said Lowe. "That he doesn't eat as well, he looks skinnier, he's lost his hair.