Real went through on a 3-1 aggregate score after making good on their 2-0 win in the first leg.
Barcelona: Real Madrid overcame the loss of goalkeeper Iker Casillas and two dismissals to reach the Copa del Rey semifinals after drawing 1-1 at Valencia on Wednesday, setting up a possible clash with archrival Barcelona.
Real went through on a 3-1 aggregate score after making good on their 2-0 win in the first leg despite losing Casillas to a hand injury in the 13th minute.
Also, Sevilla thrashed nine-man Real Zaragoza 4-0 with striker Alvaro Negredo scoring twice to also make the semifinal round.
Striker Karim Benzema opened for Real a minute before halftime, but the game swung in Valencia's favor when Fabio Coentrao received his second booking in the 51st.
Midfielder Tino Costa scored the resulting free kick, which backup goalkeeper Adan Garrido let slip under him.
Real had little trouble resisting Valencia's revival even with 10 men. Jose Mourinho's team ended with nine players when Angel Di Maria saw red for tripping Joao Pereira in the 88th.
Real will face the winners of the tie between Barcelona and Malaga. The two meet in La Rosaleda Stadium on Thursday after drawing 2-2 in the first leg.
"We went in with an advantage from the first leg, and the first goal put us well on our way," said Real midfielder Xabi Alonso, adding that he hoped Casillas' injury "wasn't too serious."
It was Real's third game against Valencia in nine days, after thrashing Ernesto Valverde's team 5-0 in the league on Sunday.
Both sides traded shots early on with Real's Cristiano Ronaldo drawing a parry from goalkeeper Vicente Guaita, while Nelson Valdes - starting for the injured Roberto Soldado - threatened with a pair of headers.
Casillas was forced out when teammate Alvaro Arbeloa inadvertently kicked his left hand while clearing a dangerous loose ball in front of Madrid's goal. Madrid assistant coach Aitor Karanka said Casillas needed to undergo tests to determine the injury.
Real went ahead when Valencia defender Ricardo Costa failed to intercept Xabi Alonso's pass to Benzema, leaving the France striker alone to stroke the ball past Guaita.
Benzema's score gave Real an all-important away goal to practically crush any thoughts of a Valencia comeback.
Even so, Valencia showed spirit toward the end after pulling one back through Costa's free kick, and a good deal of help from Adan, who should have done more to prevent the equalizer.
Valencia forward Sergio Canales went on in the 69th for his first action since tearing a left knee ligament a second time last April.
"On a personal note, I'm happy. I've been preparing for eight months for this moment," said Canales, a former Real player. "But as far as the game went, it's a pity. We had placed a lot of hope in this series."
After drawing 0-0 with Zaragoza in the first leg, Sevilla dominated their second meeting to give coach Unai Emery a stellar home debut at Sanchez Pizjuan Stadium.
New signing Jose Fernandez left Zaragoza with 10 men from the 25th minute when he saw red for a studs-first tackle of Jose Antonio Reyes.
Negredo headed in Ivan Rakitic's corner to open in the 35th, and Rakitic then added a second on the break in the 47th.
Negredo scored a penalty in the 67th after Fran Gonzalez was sent off for fouling Cicinho in the area, before Manu del Moral capped the win in injury time.
Sevilla will face either Atletico Madrid or Real Betis next. Atletico lead their tie 2-0 going into Thursday's second leg.