The Red Devils will also be in action against Lens at Old Trafford on Saturday, with Erik ten Hag's side building towards their league opener against Wolverhampton Wanderers on August 14, while Athletic will begin their La Liga season at home to Real Madrid on August 12.
Match preview
Man United's pre-season tour of the United States came to an end last Sunday, suffering a 3-2 defeat to Borussia Dortmund, with the result following a 2-0 reverse to Real Madrid.
Red Devils head coach Ten Hag will not be too concerned about the results in pre-season, but there is no question that winning breeds confidence, and he will be aiming for two victories this weekend against Lens and Athletic before welcoming Wolves to Old Trafford in the Premier League on August 14.
Ten Hag's plans for the two friendlies this weekend are unclear at this stage, but it is believed that a second-string outfit will start against Athletic, with the bulk of the first-team players featuring against Lens.
Man United are expecting to confirm Rasmus Hojlund as their third signing of the summer transfer window on Saturday, with the Denmark international set to follow Mason Mount and Andre Onana in joining the club this summer, and there could be more incomings before the transfer window slams shut.
The Red Devils will know the importance of making a strong start to the season considering their back-to-back losses in their opening league two games last term, and two victories in their friendlies this weekend would leave the team in a confident mood ahead of the clash with Wolves.
Athletic, meanwhile, have been busy this summer in terms of friendlies, playing six times in total, but they have only won once, which proved to be a 2-0 success over Necaxa on July 20.
Since then, the Basque outfit have drawn with Racing Santander and Eibar, in addition to losing to Gimnastic Torrelavega and Celtic, and the clash with Man United on Sunday will bring an end to their pre-season.
Ernesto Valverde's side finished eighth in La Liga last term, two points behind seventh-placed Osasuna, and they will be expecting to challenge for a possible European finish again in the new season.
Athletic's Basque-only policy in the transfer market makes it difficult for them to boost their squad, but Inigo Ruiz de Galarreta has arrived from Mallorca, while Javier Marton has moved from Real Sociedad B.
Inigo Martinez has been their major departure, with the centre-back joining Barcelona on a free transfer, but the likes if Inaki Williams and Nico Williams have stayed at the club, and the team will be bidding to secure a positive result this weekend ahead of their 2023-24 La Liga opener against Real Madrid on August 12.
Manchester United friendly form:
W
W
D
L
L
L
Athletic Bilbao friendly form:
Team News
Man United will again be without the services of Dean Henderson, Tyrell Malacia, Amad Diallo and Kobbie Mainoo for Sunday's clash in Dublin due to injuries.
Ten Hag is expected to start arguably his strongest available XI against Lens on Saturday, which could lead to a second-string outfit taking to the field for the first whistle against Athletic.
There will still be plenty of familiar faces in the shape of Diogo Dalot, Harry Maguire, Victor Lindelof, Scott McTominay and Christian Eriksen, though, while there is a slight chance that Hojlund could make his first appearance for the club if his arrival is confirmed on Saturday.
Athletic, meanwhile, are likely to have their two new signings on display in this match, with Ruiz de Galarreta likely to start in central midfield and Marton potentially appearing off the bench.
Head coach Valverde will pick a team with the clash against Real Madrid in mind, so Inaki Williams, Oihan Sancet, Nico Williams and Mikel Vesga should be among those to start.
Gorka Guruzeta could lead the line for the La Liga outfit, although Asier Villalibre is also an option in the final third of the field, while Iker Muniain and Alex Berenguer will also feature at some stage of the contest.
Manchester United possible starting lineup:
Heaton; Dalot, Maguire, Lindelof, Fernandez; McTominay, Hannibal, Eriksen; Pellistri, Hugill, Forson
Athletic Bilbao possible starting lineup:
Simon; De Marcos, Vivian, Yeray, Yuri; Vesga, D Garcia; I Williams, Sancet, N Williams; Guruzeta
We say: Manchester United 2-2 Athletic Bilbao
Man United are not expected to be at full strength on Sunday, but there will still be plenty of familiar faces, and the Red Devils have such a strong squad that it should be a very competitive fixture. Athletic have goals in them but can also be suspect defensively, so we are predicting a high-scoring draw here.