Athletic Bilbao, who are seventh in La Liga, dished out a footballing lesson to Manchester United.
When you factor in Fernando Torres-esq misses from Óscar, Andoni Iraola and Toquero, 2-1 is a nice scoreline.
Here are the five reasons why Sir Alex Ferguson's men were beaten.
Park Ji-Sung couldn't even stop himself from tripping every 10 or so minutes, let alone putting in a somewhat decent shift in midfield.
Not only was he nonexistent but he was a liability.
I've never seen Park play so terribly. He was so bad that he should have been subbed off after 25 minutes.
Either tell Paul Scholes to drink an elixir or life, or start Paul Pogba.
No more Park.
Rio Ferdinand was nowhere to be seen when Fernando Llorente scored a Marco van Basten-esque goal.
Even when Llorente went off inured, Ferdinand was all over the place.
He was humiliated by Andoni Iraola—a right-back!
Prior to Iraola's magical dribbling, Ferdinand was caught in possession by Toquero.
By being subbed off with 30 minutes to go, Ferdinand was spared from further agony.
Why give Patrice Evra the captaincy when he doesn't care?
He gives the ball away and he doesn't track back. There were times in the game where he didn't even put in an attempt to stop a cross.
Where was the passion? Where was the leadership?
Athletic Bilbao's dynamic pressing style is extremely similar to that of André Villas-Boas' Porto side.
The main inspiration stems from Barcelona but Bilbao ran themselves into the ground just to win back possession.
Not only did Manchester United turn over the ball needlessly, but they weren't given enough space to play incisive passes.
When Athletic Bilbao's right-back Andoni Iraola danced his way into Manchester United's penalty box, it demonstrated how technically adept the Bilbao players were.
It's a surprise to anglocentric football viewers, but it's no surprise to football aficionados.
Bilbao taught Manchester United how to play football in the first leg and the second leg.
Tactically, Marcelo Bielsa has prepped every single one of his players on their role from a defensive and attacking perspective.
To Manchester United's credit, they made the scoreline look relatively close in both legs.