Barcelona's dismal season hit yet another low after they crashed out of the Copa Del Rey to Athletic Club, losing 3-2 after extra time at San Mames.
Xavi Hernandez's side were second best for much of the Round of 16 encounter, with their ageing defence tested time and again by the pace and trickery of Nico Williams.
And though they showed fight to twice get back on terms, Iker Muniain's late penalty was one bridge too far to recover from.
It was quite the start at San Mames, with Muniain lighting the blue touchpaper by putting his side ahead with just two minutes on the clock.
It was a fine curling finish from the 29-year-old following good work down the right by the industrious Nico Williams.
But anything Muniain could do, so too could Ferran Torres.
Barcelona had barely been in the game but receiving the ball from Sergio Busquets on 20 minutes, Ferran turned and lashed into the far corner giving Julen Agirrezabala no chance.
With Nico Williams continuing to cause chaos down the right the hosts could quite conceivably have gone into the break ahead, but they had to wait until the last five minutes of normal time to get their just desserts.
Muniain's freekick found Alex Berenguer who saw his header saved by Marc-Andre ter Stegen, but the Barcelona keeper couldn't stop Inigo Martinez bundling the rebound over the line.
It looked like being another dagger to the heart of the Blaugrana but somehow, from somewhere, they dug out a scarcely-deserved equaliser at the death through Pedri.
It took the game to extra-time, whereupon the hosts forced their spot-kick after a handball from Jordi Alba, and Muniain showed nerves of steel to slot past Ter Stegen.
Barcelona pressed in the final stages in search of an equaliser but to no avail, and they will now lick their wounds and resume their battle to finish in the top four of LaLiga Santander - itself no foregone conclusion.