Athletic Bilbao must be wary of a wounded Barcelona desperate to make amends for a disappointing Supercopa de Espana defeat by starting their Liga defence in style.
Luis Enrique's Barca slumped to a 5-1 aggregate loss against Bilbao in the Supercopa, following a 4-0 rout at San Mames last Friday.
The Catalan club were perhaps weary in that fixture having triumphed in a thrilling 5-4 extra-time victory over domestic rivals Sevilla in the UEFA Super Cup in Tbilisi three days earlier.
Nevertheless, Barca will want to show that the first-leg loss in Bilbao was a freak result when they return to San Mames on Sunday to play Ernesto Valverde's side for the third time in 10 days.
"Athletic are a tough team and the best we can do is come back, play good football, and get the three points," centre-back Marc Bartra said.
"When things don't go very well one day, I really want to have another shot at that day. Barca are lucky enough to be competing again very quickly and there are lots of ways we can learn from our mistakes.
"We play well as a team and we make mistakes as a team as well. We have to improve in all aspects and try to avoid individual errors."
Despite last week's defeat to Bilbao, it would take a brave man to bet against Barca returning with three points on this occasion.
Barca were 5-2 victors at San Mames in February during an incredible 2014-15 season in which they secured a Liga, UEFA Champions League and Copa del Rey treble, beating Bilbao in the final of the latter.
Lionel Messi, Luis Suarez and Neymar were all on target in the league rout, the trio collecting three of the record 122 goals they scored between them during the campaign.
However, Brazil star Neymar is missing on this occasion due to mumps, and Luis Enrique has other problems to contend with.
Centre-back Gerard Pique starts a four-match ban - that Barca have appealed against - for insulting a linesman in the second leg of the Bilbao tie, while Jeremy Mathieu is suspended for one game due to an accumulation of cautions from last season.
With Adriano and Jordi Alba injury doubts, Barca could be short in defence, while the sale of Pedro to Chelsea on Thursday means their attacking options have also been weakened.
Bilbao, who finished seventh last season, will hope to make the most of those absentees and bounce back from a disappointing 3-2 loss at Zilina in a UEFA Europa League qualifier on Thursday.
Bilbao had led 2-0 after 33 minutes, but were left reeling by a shock comeback in the last 24 minutes - with a Jakub Paur strike and Willian's double doing the damage.
