The Catalans led twice, but were pegged back on each occasion by the Brazilian outfit before prevailing in a shoot-out. Thiago and Jonathan dos Santos scored for the Spanish side
Barca had twice led, in the first half through Thiago Alcantara and in the second period thanks to Jonathan dos Santos, but the South Americans hit back on both occasions with goals from Nei and Leandro Damiao to take the match to the penalty shoot-out, which the Catalans prevailed 4-2.
Barca coach Pep Guardiola named a different line-up in each half, as he had done in the weekend goalless draw with Hajduk Split, but it was a stronger side this time, with Andres Iniesta, Sergio Busquets, Victor Valdes and Ibrahim Afellay all included.
There was also a place for striker Jonathan Soriano, who had starred with Barca B last term and could yet have a future at Camp Nou. The former Espanyol man linked up well with Iniesta in a first period dominated by the Catalan club.
But it was Thiago who gave Guardiola’s side the lead as he found himself all alone in the area and kept his cool to beat Inter keeper Muriel after a quarter of an hour.
The Brazilians hit back after the break, when Tottenham target Damiao forced Jose Pinto into an error and Nei fired home from close range.
Jonathan then made it 2-1 as he latched onto Carlos Carmona’s pass and beat Muriel after 62 minutes, but Inter fought back late on and Damiao headed home from a corner following another Pinto error.
David Villa, Jonathan, Carmona and Armando all converted from the spot to give Barca the win and a final spot against either AC Milan or Bayern Munich on Wednesday.