Wednesday's Champions League semi-final meeting between Atletico Madrid and Bayern Munich promises to be an enthralling clash of styles, as Europe's tightest defence takes on one of its most advanced and versatile attacks.

In Arturo Vidal, Bayern have a player who bridges the divide, someone whose all-action, more blood and thunder and less cerebral approach could easily fit in at the Vicente Calderon, and who is perhaps a more natural match for the Rojiblancos than he is the German champions.

Previous form suggests the Chilean could well prove to be Pep Guardiola's key weapon in unlocking the Colchoneros' famously stubborn rear-guard this week however, his tie-winning displays in Bayern's last Champions League matches with Benfica provides a good indicator of how his unique qualities can help break down more rigid opponents.

Vidal's recent Champions League form is a far cry from where he was only a couple of months ago, derided as a flop and questioned for his attitude off the pitch. The €37m price tag required to bring the player from Juventus to Bayern last summer didn't help, raising expectations among pundits and supporters, particularly when combined with his role in Chile's 2015 Copa America win. When he initially struggled to reproduce the quality that had convinced Bayern to move for him in the first place, it didn't take long for the critics to chime up.

The name of one of those critics will come as little surprise. In September, Franz Beckenbauer complained to Sky Deutschland that Bayern "don't need footballers who don't move" while referring to Vidal, adding that "the hope in him was higher".

That forced Guardiola to publically defended his player, and for the next few months the Catalan stood by him on the pitch, starting the former Juve man in the majority of Bayern's games. Yet as the season rolled on, the Chilean only further struggled to convince, and to make matters worse, stories of after-hours exploits began to gather steam following the turn of the year.

Rumours in the German tabloids claimed that Vidal had spent much of his time during Bayern's Qatar-based winter training camp out drinking. The midfielder firmly denied the claims, but regardless of their veracity, the added noise did little to help his tricky bedding-in at the Allianz Arena.

Then there were suggestions that he was the player leaking dressing room information to the press, while in February there came more tales still, this time of a night out with David Alaba and Franck Ribery that ended in the early hours of the morning while Bayern were in Turin to play Juventus.

Distractions off the pitch combined with a continued failure to perform at the level expected of him on it didn't paint a pretty prognosis of how Vidal's Bayern career was going to work out. His toils even led one well known pundit to compare him to "Las Vegas Elvis", labelling him "an expensive misfit, cumbersome and without the technical ability of his peers".

Ironically enough, it was not the technical ability of his peers, but the things that make Vidal different from many of them that helped Bayern to edge past Benfica in the Champions league quarter-finals a couple of months later.

The Eagles were a useful sample of what is to come for the Bavarians this week, their solidity not a million miles away from Atletico Madrid. Appropriately, it was that discipline that allowed the Portuguese side to go to the Vicente Calderon last December and take a surprise 2-1 away win, their counter-attacking beating Atletico at their own game.

In the Bayern tie, Benfica stayed true to type, quite often proving successful in their attempts to stifle. The one player they couldn't handle however was the one who was capable of attacking them in a different way. The only goal of the German champions' 1-0 first leg win over Rui Vitória's side came not through Robert Lewandowski, Franck Ribery or Thomas Muller, but through Vidal, steaming into the area like a freight train to head the ball into the back of the net.

He sent a similar chance just over the bar later in the game, Benfica clearly struggling to cope with his secondary runs into the box, and the second leg would only confirm how useful his movement could be for Bayern in these kind of ties.

At the Estadio da Luz, Vidal's box-to-box play was a constant threat, and when he smashed home a half-volleyed strike from the edge of the area just before the break, the potential for him to find and capitalise upon pockets of space was made clear.

Guardiola pointed out afterwards that Vidal is particularly good at making those kind of late runs, and it is exactly that sort of play that Pep will hope to use to good effect against Atletico. In static build-up (moves not launched via a quick transition from defence to attack) the Colchoneros are incredibly difficult to break down. If Bayern's attacking play is too predictable, it will simply be sucked up by Diego Simeone and spat back out at them.

The Bavarians will likely need to mix things up to pick the Atletico lock, therefore, and that is where Vidal and his last-minute arrivals in the area come into play. On paper, the Chilean could be the key to a first Bayern final since 2013. Though whether a footballer who is known for his hot head can avoid being drawn into Atleti's mind games is a different question.

Lee Roden is a freelance Spanish and European football writer. You can follow him on Twitter @LeeRoden89