Barcelona earned a 3-1 win at Alaves in La Liga on Saturday with Brazilian teenager Vitor Roque scoring and then sent off in a lively appearance off the bench.
Samu Omorodion pulled a goal back for the hosts before 18-year-old striker Roque pounced and a few minutes later was harshly dismissed.
Barcelona's victory helps them cut the gap on league leaders Real Madrid to seven points before Los Blancos face Atletico Madrid in a derby clash Sunday.
They have won both of their matches since Xavi announced last weekend he would leave the club at the end of the season.
"It has nothing to do with (Xavi departing)," Barcelona defender Jules Kounde told DAZN.
"The team knows that we have to recover what was our strength last year, which is defending well and competing.
"However much talent you have in the team, we play against talented teams too that also have soul -- at this ground you have to have soul and we had it today."
Xavi selected Andreas Christensen in defensive midfield for the first time in his Barcelona career, with the Catalans still unable to find a reliable replacement for Sergio Busquets.
The Danish defender was solid and showed Xavi he is an option for the future in the role, ahead of the out-of-favour Oriol Romeu.
Alaves, 12th, started quickly and put the visitors on the back foot in the early stages, but could not capitalise on their pressure.
Barcelona took the lead when Lewandowski delightfully dinked home after a good team move, with Gundogan threading a pass through to him.
It was the veteran forward's first goal in La Liga since October, when he netted in a 4-2 defeat by surprise title challengers Girona.
The Catalans struck again after the break when Pedri scooped a fine ball to the back post for Gundogan, who did well to keep a controlled volley under the crossbar.
Alaves instantly hit back with Omorodion heading home Alex Sola's cross after escaping the attentions of Barcelona defender Ronald Araujo.
- Roque road -
Xavi's side kept their heads up and grabbed the third through substitute Roque, who arrived in the January transfer window from Brazilian side Athletico Paranaense.
Electric 16-year-old winger Lamine Yamal turned brilliantly to start an attack which culminated when Roque finished coolly from Hector Fort's pass.
Roque's cameo from the bench lasted less than 15 minutes, after he was shown two yellow cards.
The second was for a supposed foul on Rafa Marin which appeared an innocuous challenge, but there was no video review as VAR cannot ask officials to check second yellow card incidents.
Later Saturday Girona, second, can overtake Madrid provisionally if they beat Real Sociedad at home.