The record domestic Cup winners with 26 titles, Barca are 2-0 up on Real Sociedad ahead of their semi-final second leg in San Sebastian on Wednesday.
Real, who have claimed the trophy 18 times and are third on the all-time list behind Athletic Bilbao with 23, have a 3-0 cushion before their trip across the capital to play holders Atletico Madrid on Tuesday.
As well as revenge for last season's 2-1 defeat in the final, Real's convincing performance in last week's first leg at the Bernabeu was the latest evidence they are coming into form just as the season is approaching a critical juncture.
Barca suffered a surprise wobble in La Liga at the beginning of the month, losing 3-2 at home to Valencia, but have made serene progress in the Cup and returned to the top of the league thanks to Sunday's impressive 4-1 comeback win at Sevilla.
Their four-time World Player of the Year Lionel Messi has taken time to get back into his stride following a two-month injury layoff around the turn of the year but his superb double in Seville suggested he is not far off his scintillating best.
"If anyone says anything negative about him all they are doing is provoking him," Barca coach Gerardo Martino, who hails from Messi's home town of Rosario in Argentina, told a news conference.
"And if you provoke the world's best player his next opponent will have a problem.
"He is always decisive, even if it is merely a matter of dragging opposition players into the centre and anything that distracts their attention is positive."
Real also look to have their latest "galactico" signing, Wales winger Gareth Bale, back to full fitness after a series of minor niggles.
The world's most expensive player opened the scoring in Saturday's 4-2 La Liga win at home to Villarreal and set up Karim Benzema for the second of the night.
"I scored a fantastic goal and made an assist," Bale told reporters. "I am very pleased and available for the coach for our upcoming games.
"I am working hard on the pitch and in every training session so I can be in the team."
Once the Cup semi-finals are out of the way, Barca have one more La Liga game, at home to struggling Rayo Vallecano, before they play at Manchester City in the last 16 of the Champions League on February 18.
Real play at Getafe and host Elche in La Liga before their trip to Germany to meet Schalke 04 on February 26.
- Sports & Recreation
- Real Sociedad
- La Liga
- Lionel Messi