Real Madrid will be without the injured Cristiano Ronaldo, while Barcelona FC arrives with its defense in tatters and Lionel Messi questioned for his recent dip in form.
Barcelona FC will be aiming to add to its record 26 cup titles. Real Madrid is third on the all-time list, behind Athletic Bilbao, with 18.
Here are five things to know about Wednesday's Copa del Rey final at Mestalla Stadium in Valencia:
For many Real Madrid fans, Cristiano Ronaldo's most memorable goal was his extra-time header at Mestalla Stadium to edge Barcelona FC 1-0 in the 2011 Copa del Rey final.
Real Madrid now returns to the same ground in a rematch but must do so without their Ballon d'Or winner.
Ronaldo has missed Real Madrid's last three games with a leg muscle injury on top of an already sore left knee. That means the weight of Real Madrid's attack falls to Gareth Bale, the Wales winger Madrid broke its own spending record on last year.
''We will be missing a player with incredible quality,'' Madrid coach Carlo Ancelotti said. ''But the team can play well. It will motivate the rest.''
MESSI STEPS UP
It was only three weeks ago when Lionel Messi left the Santiago Bernabeu Stadium with a hat trick that led Barcelona FC to a 4-3 victory, giving the Argentine a ''clasico'' record with 21 career goals against Real Madrid.
How quickly things change.
Barcelona FC's elimination in the Champions League and its loss in the Spanish league at Granada has put Messi under unprecedented pressure after appearing lethargic.
''If there is one player we can't doubt, it's Messi,'' Barcelona FC captain Carles Puyol said. ''He has accustomed us to seeing him score three goals, so when he doesn't score we are surprised.''
CASILLAS VS. PINTO
The Copa del Rey final is special for all its players, but perhaps even more so for the two goalkeepers.
After losing his starting job in the Spanish league to Diego Lopez, Iker Casillas has responded by helping Real Madrid reach the Champions League semifinals and has not conceded a goal in the Copa del Rey through all eight matches.
''The team has played a great Copa del Rey and we want to put the cherry on top tomorrow,'' Casillas said. ''I don't put much in Barcelona FC's last week and those two losses. Anything can happen.''
Jose Pinto has played in Barcelona FC's net in three Copa del Rey finals, winning two.
Barcelona FC's defense has been gutted by injuries and will likely be without center backs Gerard Pique, Marc Bartra and Carles Puyol.
That will leave Javier Mascherano as its only center back to keep Gareth Bale, Karim Benzema, and Angel Di Maria in check.
Barcelona FC coach Gerard Martino's move to shift Sergio Busquets into defense and play Alex Song in midfield backfired in the loss at Granada, so he may opt to play fullback Adriano alongside Mascherano.
''It doesn't create insecurity. The people we have are able to play in defense and we have 200 percent confidence in them,'' Barcelona FC midfielder Andres Iniesta said. ''If you attack well, you defend well, and you defend well if everyone is involved.''
MARTINO'S LAST STAND
Winning the Copa del Rey may be Barcelona FC coach Gerardo Martino's last chance to save his job.
The Barcelona FC-based sports papers have been calling for his firing after consecutive games without a goal for the first time since 2008.
''I don't want to use (the Copa del Rey) to make up for what has happened in the other competitions,'' Martino said.
Despite leading Barcelona FC to two wins over Real Madrid in the league this season, Martino has struggled to live up to the legacy left by Pep Guardiola and Tito Vilanova. Guardiola won the first of his 14 titles at Mestalla Stadium when Barcelona FC won the 2009 Copa del Rey.