Barcelona second-string players Andreu Fontas and Victor Vazquez scored in a 2-0 win over Rubin Kazan on Tuesday to ensure the Spanish club ended the group stage of the Champions League unbeaten.
Barcelona had already sealed top spot in Group D, ensuring coach Pep Guardiola selected mostly reserve players and they completed the team's first win in four attempts against the Russian club.
Rubin finished third in the group and will play in the Europa League.
Fontas scored in the 51st minute, receiving a pass from Thiago Alcantara and hitting a shot that bounced off a Rubin player before trickling across the goal line.
Vazquez sealed the victory in the 82nd minute with a low right-footed strike.
With no result to play for, Guardiola rested starters Xavi Hernandez, David Villa, Dani Alves, Pedro Rodriguez as well as often used midfielder Seydou Keita. Youngsters Bojan Krkic and Jeffren Suarez started in attack while Thiago and Fontas debuted in Europe and Jonathan dos Santos made his second appearance in the competition.
"I am satisfied because players that deserve to play but don't have a lot of chances today had the opportunity to play against a tough opponent, and we could see that took the game seriously," Guardiola said. "It says a lot about these players that we were finally able to beat such a good defensive team with people that are so young."
Guardiola also took the opportunity to experiment with a 3-4-3 formation that had Gerard Pique, Sergio Busquets and Fontas at the back.
Even though Rubin was the side in need of points, the Russians were content to let Barcelona have the ball and wait for a counterattack that never came.
Barcelona dominated the possession in a slow-paced opening, but the visitors shared the few scoring chances thanks to various incursions by left back Cristian Ansaldi, who almost sneaked a low shot at a tight angle past Pinto's left post after 15 minutes.
Thiago, along with an active Adriano, provided the little spark Barcelona had in attack. The 19-year old Thiago forced Rubin goalkeeper Sergei Ryzhikov into a diving save with a low shot from the edge of the area in the 18th minute.
Barcelona's first half saw more injuries than scoring opportunities. Guardiola had to change both Suarez and Krkic, who left his team without a natural striker.
With Bojan's exit in the 32nd, Barcelona switched back to its standard four-man defensive line to stop Rubin's attacks down the left side.
Guardiola said the line of three defenders "wasn't working because we weren't attacking well, and with the move to a four-man line, we were a little more comfortable."
Barcelona came out more aggressively in the second half and soon went ahead through Fontas' goal.
"My debut (in Europe) could not have been better," Fontas said. "There were some nerves maybe at the beginning, but later everything changes and with my teammates everything is easier."
Lionel Messi entered for Jonathan dos Santos in the 63rd, but moments later Rafal Murawski wasted Rubin's best chance of the game when he failed to get off a good shot in a one-on-one with Pinto.
Messi almost doubled Barcelona's lead with a shot that went wide of the left post two minutes after coming on.
However, Barcelona didn't need Messi's goals on this occasion. Vazquez, who had come on in the first half, went on to score the second after linking up with Adriano.
Rubin coach Kurban Berdyev said that Barcelona's young players all had potential.
"You notice that they are from the Barcelona school of football, they all know exactly what to do in each moment," Berdyev said.
