Wilfrid Kaptoum struck an 84th-minute equaliser as Barcelona secured their spot in the 2016 Copa del Rey final courtesy of a 1-1 draw at Valencia in Wednesday's semi-final second leg.
Luis Enrique's side were 7-0 winners in the first leg last week, which all but secured their spot in the final ahead of the return, rendering it almost a free match for both teams.
The Catalan outfit's 28-game unbeaten run was under threat after a first-half strike from Alvaro Negredo looked to be securing a vital win for under-fire Los Che boss Gary Neville, but Kaptoum came off the bench to score his first Barcelona goal late on.
With Barcelona sure of a spot in the final, both managers made sweeping changes to their XI ahead of important La Liga games at the weekend.
It was a mix-and-match Valencia side, although Negredo and Jose Gaya were both included. As for Barcelona, Lionel Messi, Luis Suarez and Neymar were all rested in a side that showed nine changes from the one that beat Levante in the league at the weekend.
Sergi Samper, Munir El Haddadi and Sandro Ramirez were all given chances to impress, while it was an entirely new back five for the holders of the competition.
Munir set up Sandro for the first real chance of the match inside four minutes, but the Spanish youngster could only curl over the crossbar from the edge of the penalty box, before Ivan Rakitic came close with a strike from distance in the 10th minute.
Seventeen-year-old Fran Villalba had Valencia's first shot inside 15 minutes, but it sailed over the crossbar during a period where the hosts were struggling to keep hold of the ball.
Munir was next to come close for Barcelona in the 19th minute, but the attacker's strike from distance, which arrived after some excellent foot-work, was always rising over the crossbar.
Santi Mina looked certain to send Valencia ahead from close range in the 22nd minute, but somehow Jeremy Mathieu made a goal-line clearance to prevent Pablo Piatti's cross from reaching the Spaniard.
Villalba again came close for the hosts 15 minutes before the break when he worked a yard of space outside the box before having a go, but once again, the teenager's effort was over the crossbar.
The home side did take the lead on the night in the 39th minute, however, when Negredo beat the offside trap and converted from close range after initially being denied by Marc-Andre ter Stegen.
Munir had a golden chance to level the scores in the latter stages of the first period when he met a free kick from Adriano, but the youngster somehow headed wide from close range as Los Che took a one-goal lead into the interval.
Mina came close to sending Valencia 2-0 ahead early in the second period after meeting a cross from Piatti, but the forward's header flew wide of the target.
It was the hosts that continued to look the more likely to add to the scoring as the hour mark approached, but Barcelona had a couple of half-chances through Rakitic, who did not have his shooting boots on at the Mestalla.
Piatti had the opportunity to double Valencia's lead from a free kick 20 minutes from time, but the Argentine curled over Ter Stegen's crossbar as Barcelona remained within one goal of their opponents on the night. Danilo came even closer with a free kick of his own moments later, but Ter Stegen was on hand to make a fine stop.
Valencia looked to have done enough to record a vital win, but Kaptoum had other ideas as the 19-year-old notched his first senior goal in the 84th minute after an excellent low cross from fellow youngster Juan Camara.
