Barca's place in a fifth final in six years was assured after a 7-0 first-leg annihilation last week. Uruguay international Luis Suarez scored four and Argentina skipper Lionel Messi got three in the demolition of Gary Neville's side.
The former Manchester United and England defender described the defeat as one of his worst nights in football. And the humiliation continued on Wednesday at Valecnia's Mestalla stadium.
The Barcelona coach Luis Enrique left Messi, Suarez and the Brazil striker Neyam back home. Andres Iniesta, Sergio Busquets and Gerard Pique were also omitted.
Valencia's fans showed their wrath too. Only 16,000 of them were dotted around a stadium that can hold 55,000.
The brave souls who did turn out were rewarded just before half-time when Alvaro Negredo scored. However, 19-year-old Cameroonian midfielder Wilfred Kaptoum came off the bench to score his first Barca goal and preserve the European champions unbeaten run six minutes from time.
"I'm very happy to be in the final," said Enrique. "Everyone at Barca has had things so good in recent years we are used to reaching the final. But it is hard to be there every year."
Last season, Enrique led the Catalans to the Uefa Champions League title as well as the Spanish championship and the Copa del Rey. They've also claimed the Club World Cup and the European Super Cup.
Valencia are vapid in comparison. They have not won for 12 league games, including nine since Neville took charge in December.
Neville also left out some of the most important members of his squad for the crucial clash at home to Espanyol on Saturday.
"We are preparing the game already for Saturday, we know it is a big match," he said. "The focus after losing last week in Barcelona and on Sunday at Real Betis has been the match on Saturday against Espanyol.
"They weren't perfect circumstances after last week, but the players played with dignity."
Sevilla are well-set to meet Barcelona in the final on 21 May. They travel on Thursday night to Celta Vigofor the second-leg of their semi-final with a 4-0 lead.