Lamine Yamal and Ronald Araujo goals helped Barcelona reach the Copa del Rey semi-finals with a nervy 2-1 win at Albacete on Tuesday.
The record 32-time cup winners were pushed to the end in a tight quarter-final clash by their second division opponents, who stunned Real Madrid in the previous round.
Yamal fired Barca ahead just before half-time and Araujo headed home the second early after the break on his first start since taking a month-long mental health break at the end of last year.
Albacete created several chances in the last half hour and Javi Moreno headed home with three minutes to go to give Hansi Flick's Barca a scare.
"The last few minutes... it's normal, they got a goal, the cup is like this," Araujo told Barca's media channel.
"I'm very happy (to start again), it was an important step... a hug to the coach, he helped me a lot."
Holders Barca spurned some fine chances, just as they did in their win over Elche in La Liga on Saturday.
"It was a tough match at the end, it was very hard. We could have made it much easier for ourselves, we missed many chances, but I think also we deserved (to win)," said Flick.
"I'm happy, proud of the team and we're in the semi-finals, and that's the best thing."
Barcelona controlled the game in the first half but could not easily break down Albacete's resistance.
Marcus Rashford spurned a couple of decent openings in the opening few minutes, and after that the hosts shut up shop against Flick's side.
Spanish champions Barcelona's brightest player was, as usual, teenage star Yamal, and he struck in the 39th minute.
Rashford pressed well to win the ball back, and Frenkie de Jong's pass bobbled into Yamal's path for the 18-year-old to curl home.
Antonio Puertas got in behind Barcelona's defense at the other end but took a heavy touch and goalkeeper Joan Garcia was able to snag the loose ball.
The stopper accidentally gave away a corner as he walked off the pitch with it to pat Araujo on the head, in a comical moment before the break.
Dani Olmo should have doubled Barca's lead early in the second half when Rashford put the ball on a plate for him but his shot was blocked.
Puertas's volley deflected off De Jong and just over Garcia's goal as the hosts threatened sporadically.
Araujo headed in Rashford's corner as Barcelona doubled their lead and seemed set to cruise to victory, before some late Albacete resistance threatened an upset.
- Holding on -
Jefte Betancor, who scored Albacete's stunning winner against Real Madrid, cut inside Araujo and whipped a shot just wide.
Puertas put the ball in the back of Barca's net with seven minutes to go but there was an offside earlier in the move and it was disallowed.
Albacete finally scored in the 87th minute when Moreno's powerful header from Jose Lazo's free-kick flew past Garcia, but they could not find another to force the game to extra-time.
Gerard Martin headed Fran Gamez's effort off the line as Barca endured a nervy five minutes of stoppage time to triumph.
"We have to finish with more conviction," said Flick, who said he was happy that Araujo netted on his return to the starting line-up.
"He scored a very important goal for us, it could help him to get more confidence and believe in himself," added the German coach.
In the other quarter-finals Valencia welcome Athletic Bilbao and Real Sociedad visit Alaves on Wednesday, while Atletico Madrid travel to face Real Betis on Thursday.
