The Blaugrana have not won the competition since 2018, losing their last final appearance to Valencia two years ago.
The only absentee will be Philippe Coutinho, with the Brazilian likely to miss the entirety of the season, having perhaps played his last game in a Barcelona shirt.
Barca have had great success using a back three in recent weeks and that should continue, with the added strength of Gerard Pique returning to the starting XI.
The 34-year-old hasn’t played since the beginning of March but was on the bench against Real Madrid last weekend and could be in line to start.
Alongside him could be Clasico goalscorer Oscar Mingueza and Clement Lenglet, with Sergino Dest and Jordi Alba in the wing-back positions.
In the centre, Frenkie de Jong and Sergio Busquets should continue their midfield partnership. The former has played in all 30 La Liga games so far this season, while Busquets has the equal-third most appearances with 28.
The only other player to have featured in every league fixture is youngster Pedri, and he should add to an appearance in each previous Copa del Rey tie with another start in this fixture.
Lionel Messi’s position in the starting XI speaks for itself. The Argentine has a goal and an assist in four Copa del Rey appearances to this point, also boasting the best average rating for the competition on FC with an 8.0.
The final forward position is very much up for grabs with Ousmane Dembele, Martin Braithwaite and Antoine Griezmann all in contention – each of them have scored twice in the cup.
Ansu Fati has also been named in the travelling squad, but will surely not be available to play any part in the match. The 18-year-old hasn't played since a knee ligament injury suffered in November.
Koeman can only select one, however, and it should be Griezmann that he chooses. The Frenchman has scored four goals in seven games for club and country and is Barca’s second-top goalscorer in all competitions.
Another trophy in the cabinet would do the Catalan club the world of good in what has been a very much up and down season so far, and could be the motivation they need to chase down league success.