Athletic Club's Inaki Williams and Nico Williams have been ruled out of Thursday night's Europa League semi-final second leg through injury.
The pair will miss the clash with Manchester United through hamstring and groin injuries respectively.
It makes a mammoth task even more difficult after losing the first leg 3-0.
Casemiro handed Manchester United a 1-0 lead in the 30th minute, and just five minutes later central defender Dani Vivian was sent off for denying Rasmus Hojlund a goalscoring opportunity, giving away a penalty in the meantime.
As expected, Bruno Fernandes netted from the spot, further adding to his tally in the 45th minute to hand the Red Devils a 3-0 lead.
Heading into the second leg at Old Trafford with a three goal deficit, their task of completing the impossible comeback appears even more difficult given their injury worries.
The Williams brothers have been involved in 13 of Athletic Bilbao’s 21 goals in the 2024/25 campaign, so the pair’s absence will no doubt leave Bilbao somewhat short in the attacking department.
The Basque outfit have showed signs of a lack of conviction in recent weeks, scoring just one goal in their last four games.
Maroan Sannadi led the line for Bilbao last time out against Ruben Amorim’s side, but his record of zero goals in five Europa League contests this season suggest Ernesto Valverde’s men may struggle to stage a comeback.
Nonetheless, stranger things have happened. Man Utd’s quarter-final tie at Old Trafford against Lyon served up plenty of drama, so don’t be too surprised to see a repeat.