Barcelona won opening fixture 4-2 against Real Sociedad
Athletic Bilbao drew 0-0 with Elche in their first match of the season
Athletic Bilbao v Barcelona (21:00 BST)
10,000 fans inside San Mames this evening for this one.
It's a long way off capacity, but they'll certainly make themselves heard.
Image source, Reuters
Image source, Getty ImagesAthletic Bilbao v Barcelona (21:00 BST)
These two sides may be sick of the sight of each other - it's four games already so far this calendar year.
And on that measure, Barca will be feeling confident. Three wins out of three for Ronald Koeman's men in 2021 including in the Copa del Rey final back in April.
Barca scored nine goals in those three games - five of them went to Lionel Messi, although Antoine Griezmann was also on target in the final.
He's scored more against Athletic Bilbao than any other side.
Image source, Getty ImagesAthletic Bilbao v Barcelona (21:00 BST)
Image source, Getty ImagesRonald Koeman's hands have been tied by a string of injuries to players who would expect to be in his first-choice line-up.
Summer recruit Sergio Aguero is out for at least 10 weeks with calf problems, number one keeper Andre ter Stegen is not yet fit after knee surgery in the summer and exciting prodigy Ansu Fati remains sidelined after a series of injury setbacks.
Word has it that forgotten man Philippe Coutinho could be back in the starting eleven soon - that's if he doesn't get sold first.
Athletic Bilbao v Barcelona (21:00 BST)
Frenkie de Jong, Sergio Dest, Eric Garcia and Pedri have an average age of 20 and they are the new guard spearheading Ronald Koeman's Barcelona.
The wily old heads of Gerard Pique (34), Jordi Alba (32) and Sergio Busquets (33) are still there though to help them along.
Image source, Getty ImagesAthletic Bilbao v Barcelona (21.00 BST)
Athletic Bilbao make just one change from the side that managed a goalless draw at Elche on Monday. Inigo Lekue is in for Oscar de Marcos at the back with a lot of responsibility resting on Inigo Martinez to manage a makeshift back four against the firepower of Barcelona.
Athletic Bilbao: Agirrezabala, Balenziaga, Vivian, Martinez, Lekue, Garcia, Vencedor, Berenguer, Muniain, I.Williams, Sancet.
Subs: Ezkieta, Serrano, Nunez, N.Williams, Villalibre, Zarraga, Vesga, Morcillo, De Marcos, Garcia.
Image source, BBC SportIt's the same eleven for Ronald Koeman after last week's win. If it ain't broke, don't fix it.
Barcelona XI: Neto, Alba, Dest, Garcia, Pique, De Jong, Busquets, Pedri, Braithwaite, Depay, Griezmann.
Subs: Emerson, Araujo, Puig, Lenglet, Tenas, Gaviria, Balde, Gonzalez, Demir, Manaj, Pena, Sergi Roberto.
Athletic Bilbao v Barcelona (21:00 BST)
Image source, EPAWelcome to San Mames stadium for tonight's match.
Barcelona may have got off the mark with a win but Athletic Bilbao are usually a pretty tough nut to crack.
How will Ronald Koeman's side handle the atmosphere?
Image source, EPAAthletic Bilbao v Barcelona (21.00 BST)
Crisis? What crisis?
Barcelona are reportedly more than £1 billion in debt, have a number of key men out injured and all they won last season was the Copa del Rey.
Oh and some bloke called Messi's jumped ship to Paris.
But that didn't stop them getting off to a winning start in La Liga against Real Sociedad last weekend.
Can they back it up in Bilbao this evening?
Image source, EPA