The younger Busquets, 18, is no relation to the Spain international but he does play a remarkably similar role at the base of a three-man midfield.

He was one of just two Barca B players to start the game, along with 19-year-old Carles Alena.

There were also second-half appearances for B team defender David Costas and forward Jose Arnaiz, who followed up his goal in the first leg with another brilliant strike as Barca progressed to the round of 16 with an 8-0 aggregate win.

"I'm really grateful to Sergio, he's given me a lot of advice and helped me a lot," Oriol Busquets said after the game. "I try to be like him on the pitch, but also to add my own qualities."

Busquets has been at Barca since he was eight, joining the club in 2007 and progressing through the La Masia academy during the last decade.

Currently a regular in Gerard Lopez's B team, who play in the second tier of Spanish football, he hopes Wednesday's taste of first-team action will not be his last.

"It's been a long day," he added. "I was really nervous, a lot was going through my head. Camp Nou is huge, but you just have to focus on the game. [Barca coach Ernesto] Valverde told me: 'Play like you know how to, help the team and ignore the pressure.'

"I've been here forever and my dream is to play [for the first team] and I will do everything I can to achieve it. But for now I have to enjoy this debut, things will come when they come."

Valverde was impressed by Busquets' debut but wants him to maintain his focus on performing for the B team for now.

"Busquets is a Barca style central midfielder," the coach said in his postgame news conference. "He's good bringing the ball forward, but he has to improve with his back to the game.

"He's just getting started. He has a big challenge ahead of him, playing in the second division. He could have a long career at the club and in football."

Paco Alcacer gave Barca the lead against third-tier Murcia at Camp Nou with his fourth goal of the season before the floodgates opened in the second half.

Captain for the night Gerard Pique scored the second with Aleix Vidal, Denis Suarez and Arnaiz completing the scoring.