The tie is delicately poised following a 0-0 draw in the first leg on February 6, but the two teams have met since, with Real Sociedad running out 2-1 winners in La Liga on February 18.
Match preview
Real Sociedad have, somewhat surprisingly, only won the Copa del Rey on two previous occasions, lifting the trophy in 1987 and 2020, while there have been present in a further four finals.
The White and Blues were unable to claim a first-leg advantage when they visited Mallorca on February 6, with a largely uneventful match finishing goalless.
However, as mentioned, the Basque side beat Mallorca 2-1 in the league on February 18, with that success proving to be Real Sociedad's only victory in their last seven matches in all competitions during a disappointing run.
Imanol Alguacil's side will enter this match off the back of a 3-1 home defeat to Villarreal on Friday evening, with the result leaving them in sixth position in the La Liga table, and they are in danger of missing out on European football for next season.
Real Sociedad remain active in the Champions League, but they have serious work to do if they are to advance past the round of 16, having suffered a 2-0 defeat to Paris Saint-Germain in the first leg of their last-16 clash, with the second leg due to take place in Spain on March 5.
Mallorca, meanwhile, have won the Copa del Rey on one previous occasion, lifting the trophy in 2002-03 courtesy of a 3-0 victory over Recreativo de Huelva in the final of the competition.
The Pirates have beaten Boiro, Valle Egues, Burgos, Tenerife and Girona to advance to the semi-finals of this season's Copa del Rey, with their 3-2 success over Girona last time out particularly impressive.
Javier Aguirre's side will enter this match off the back of a 1-1 draw with Alaves on Saturday; Carlos Benavidez sent the Basque outfit ahead in the 76th minute, only for Matija Nastasic to level the scores in the 88th minute.
Mallorca are currently 16th in the La Liga table, six points clear of the relegation zone, with the team in a fight to keep hold of their top-flight status for the 2024-25 campaign.
The Pirates have not managed to overcome Real Sociedad since 2012, when they thumped the Basque side 6-1 in the Copa del Rey during the 2011-12 competition.
Real Sociedad Copa del Rey form:
W
W
W
W
W
D
Real Sociedad form (all competitions):
D
D
L
L
W
L
Mallorca Copa del Rey form:
W
W
W
W
W
D
Mallorca form (all competitions):
L
L
D
W
L
D
Team News
Real Sociedad will again be missing Alvaro Odriozola, Martin Merquelanz, Aihen Munoz and Carlos Fernandez for the Copa del Rey semi-final second leg due to injury problems.
Meanwhile, Aritz Elustondo and Mikel Oyarzabal are major injury doubts, with the pair needing to undergo late fitness tests to determine their availability for the game with Mallorca.
Ander Barrenetxea was forced off in the early stages of the clash with Villarreal on Friday and is also set to miss out, but there are unlikely to be many changes from the side that started the 3-1 defeat, with Mikel Merino for Barrenetxea potentially the only alteration if Oyarzabal is unable to prove his fitness.
As for Mallorca, Pablo Maffeo is still on the sidelines with a knee injury, but Antonio Raillo and Siebe Van der Heyden have served suspensions and are available for selection.
Head coach Aguirre will make changes to the side that started against Alaves in the league, with Cyle Larin set to return in the final third of the field to partner Vedat Muriqi.
Giovanni Gonzalez, Dani Rodriguez, Samu Costa and Jaume Costa are also set to be among those to come into the side, but Sergi Darder should keep hold of his starting role in midfield.
Real Sociedad possible starting lineup:
Remiro; Traore, Le Normand, Pacheco, Galan; Mendez, Zubimendi, Merino; Kubo, A Silva, Zakharyan
Mallorca possible starting lineup:
Rajkovic; Gonzalez, Valjent, Nastasic, Copete, J Costa; D Rodriguez, S Costa, Darder; Larin, Muriqi
We say: Real Sociedad 2-1 Mallorca
Real Sociedad's recent form has been worrying, and Mallorca will be looking to take advantage of the Basque outfit's struggles on Tuesday. The home side can still call upon a lot of quality, though, and we are backing them to win 2-1 on the night to secure a 2-1 aggregate success and advance to the final, where either Athletic Bilbao or Atletico Madrid will be waiting.