Athletic occupy fifth position in the La Liga table, three points behind fourth-placed Atletico in the battle for the Champions League spots, while Barcelona sit third, eight points ahead of their opponents here and also eight points behind division leaders Real Madrid.
Match preview
Athletic were outstanding on Thursday evening, recording a 3-0 victory over Atletico in the second leg of their Copa del Rey semi-final to triumph 4-0 on aggregate, with Inaki Williams, Nico Williams and Gorka Guruzeta on the scoresheet for the Lions, who will tackle Mallorca in the final at the start of April.
Ernesto Valverde's side have four league matches before the final, though, facing Barcelona, Las Palmas, Alaves and Real Madrid before the end of March.
Athletic have only actually won one of their last three in Spain's top flight, which was a 3-2 success over Girona in their last home league fixture on February 19, but they will enter this match off the back of a 3-1 defeat to Real Betis last weekend, which proved to be their first loss in La Liga since January 20.
The Lions are currently fifth in the table, seven points ahead of sixth-placed Real Betis and just three points behind Atletico in fourth, with the team firmly in the mix for a Champions League finish.
Athletic have not claimed a top-four spot in La Liga for 10 years, finishing eighth in their last two campaigns, but they look capable of achieving a Champions League position this term.
Valverde's side have the third-best home record in the league this season, picking up 32 points from 13 matches, recording 10 wins in the process, which will hand them confidence heading into this match.
Barcelona, though, will bring a six-game unbeaten run in all competitions into this contest, with the Catalan outfit winning four and drawing two of their six matches since Xavi announced that he would be standing down as head coach at the end of the 2023-24 campaign.
The Catalan outfit's sporting director Deco has opened the door for Xavi to stay on as manager, and it is certainly a situation to watch in the coming weeks, but the head coach said after last weekend's 4-0 success over Getafe that he stands by his initial decision to move on.
Barcelona drew 1-1 with Napoli in the first leg of their last-16 Champions League contest, putting them in a strong position to qualify for the next round, with the second leg taking place in Spain on March 12.
The reigning Spanish champions have won their last two La Liga matches against Celta Vigo and Getafe, meanwhile, and they sit third in the table, just two points behind second-placed Girona and eight from leaders Real Madrid, with a title challenge still possible at this stage of the campaign.
Barcelona are unbeaten on the road in La Liga this season, winning seven and drawing five of their 12 matches, boasting the third-best away record in the division.
The Catalan outfit have won their last four La Liga games against Sunday's opponents, meanwhile, scoring 10 times and conceding zero, including a 1-0 victory at San Mames last season, and Athletic have just three league wins against Barcelona since November 2001.
Athletic Bilbao La Liga form:
L
D
W
D
W
L
Athletic Bilbao form (all competitions):
W
W
D
W
L
W
Barcelona La Liga form:
L
W
W
D
W
W
Barcelona form (all competitions):
W
W
D
W
D
W
Team News
Athletic are again set to be without the services of Yuri Berchiche and Ander Herrera for Sunday's match, with the pair both struggling with hamstring issues.
Nico Williams will also be missing through suspension due to his red card against Real Betis last weekend, while Dani Vivian picked up a milestone yellow card in the same match and will also miss out.
Alex Berenguer is expected to benefit from Nico Williams's absence to come into the attack, while Yeray Alvarez is set to replace Vivian at the back for the Lions.
There will also be a change between the sticks following the Copa del Rey success over Atletico, with the club's number one goalkeeper Unai Simon set to return in place of Julen Agirrezabala.
As for Barcelona, Gavi, Alejandro Balde and Marcos Alonso remain unavailable for selection, but Ferran Torres has a chance of being in the squad, with the Spaniard in the final stages of his recovery from a thigh issue.
Having not been in action since last Saturday, fatigue should not be an issue for Barcelona, but there could be a couple of changes for this match, with Inigo Martinez potentially returning in the middle of the defence against his former club.
Pedri is also set to return, with the Spaniard expected to replace Joao Felix down the left, but Raphinha should keep his spot on the right.
Andreas Christensen is being used as a holding midfielder at this moment in time, and he should continue in that position on Sunday, with Ilkay Gundogan and Frenkie de Jong playing either side of him.
Athletic Bilbao possible starting lineup:
Simon; De Marcos, Yeray, Paredes, Lekue; Ruiz de Galarreta, Prados; I Williams, Sancet, Berenguer; Guruzeta
Barcelona possible starting lineup:
Ter Stegen; Kounde, Araujo, I Martinez, Cancelo; F de Jong, Christensen, Gundogan; Raphinha, Lewandowski, Pedri
We say: Athletic Bilbao 1-1 Barcelona
This has all of the makings of a fascinating match, with both sides having plenty to fight for in the league. Nico Williams is a huge miss for Athletic, who have a poor recent record against Barcelona in La Liga, but we are still expecting Valverde's side to be good enough for a point on Sunday night.