It's been a week where there might not be enough superlatives to describe Spanish-based football, but Athletic Bilbao were majestic and deserving of their 3-2 win as they tore through Manchester United.
If Marcelo Bielsa was ever looking to lay down a marker for a future job at one of Europe's elite clubs, then this was it.
His side was exciting, fearless and adventurous against a Manchester United side who looked distinctly shocked at the quality of the San Mames outfit.
Javi Martinez was absolutely wonderful when his side was in possession.
He surged forward from the back-line, held his position in the centre circle to ensure the game remained in United's half of the pitch and acted as a wall that his teammates could play the ball off and resume their attack.
In defence he was strong, courageous and determined to stand his ground whenever United found themselves charging down on goal.
It was Martinez who excellently quashed a goal threat from Javier Hernandez, which then resulted in Athletic Bilbao's equaliser just before half-time.
It was a goal that was always sure to come; finished by Fernando Llorente following a nicely crafted move around the United penalty box.The Spanish striker was dominant in Athletic's attack, spear-heading the many charges and causing all kinds of problems for a United back-line who never seemed comfortable with the presence of the powerful striker.
Iker Muniain, Bilbao's very own Wayne Rooney, was like a terrier on the left side of the attack—a description that can be used for all of the team on the night—as the forward supplemented the charge with quick feet, a tireless approach, and a showcase of his ability to play in a number of attacking positions, drifting significantly infield at times to aid in all areas of the pitch.
United's opening goal felt like an injustice, such was the impressive nature of the visitors' game, starting with a Wayne Rooney free-kick played short and ending with the England striker on the end of the move.
But Bilbao continued with the relentless aggression towards their opening goal, and persisted even after the break, not wanting to sit back on their much deserved equaliser.
Almost Barcelona-like in their attacking approach, Bilbao sought to play the ball out from goalkeeper Gorka Iraizoz and moved it patiently up the field.
It really was something to behold, as Bielsa's side effortlessly played the ball from back to front.
United goalkeeper David de Gea certainly showed his quality on the night, keeping the score-line respectable and slamming the door shut on two good efforts from Llorente and Muniain after half-time.
The Bilbao fans certainly played their part: fantastic in voice and providing a small window in which to view the atmosphere that awaits Sir Alex Ferguson and his side in the second leg in the Basque country.
As Marcelo Bielsa continued his obsessive pacing up and down the technical area, he perhaps portrayed a man who was struggling to find a way to stem the tide against his side.
Instead, it was his players who were in almost absolute control, exerting a kind of exuberance and vitality that can easily be summed up through Ander Herrera's pirouette around Ryan Giggs. The veteran gave the Spanish under-21 international a pat on the back, not patronizingly, but to congratulate the youngster on his and his team-mates' performance.
What seemed to be the killer blow for the tie, Muniain adding to Oscar de Marcos' second half goal in the dying minutes, was quickly answered through a Rooney penalty and a lifeline going into the second-leg.
A fantastic encounter, not only to promote the English and Spanish games, but to enhance the reputation of the Champions League's little brother, the Europa League.
We might have seen Lionel Messi thrill the world once more as he and Barcelona smashed seven past a helpless Bayer Levekusen at the Nou Camp, but the Anglo-Basque battle that took place at Old Trafford was the highlight of an unforgettable week of European football.