Neymar scored the only goal of the match as Barcelona recorded a 1-0 victory over Manchester United in the International Champions Cup at the FedEx Field in Landover, Maryland on Wednesday night.
Neymar struck in the 31st minute of the pre-season friendly as Barcelona made it two wins from two on their tour of the US, while the defeat was United's first since arriving in the States earlier this month.
Despite ongoing speculation surrounding his future, Neymar started for Catalan side, with the Brazilian lining up alongside Lionel Messi and Luis Suarez in the final third of the field.
There was a first Barcelona start for summer signing Nelson Semedo, while young midfielder Carles Alena was handed a midfield position alongside Sergio Busquets and Ivan Rakitic.
As for United, Paul Pogba, Romelu Lukaku, Marcus Rashford and Henrikh Mkhitaryan were all included in Jose Mourinho's starting XI, in addition to Chris Smalling, who featured alongside Victor Lindelof at centre-back.
The Premier League club should have taken the lead in the third minute when Rashford drove down the right before delivering a sensational cross into the path of Lukaku, but the Belgian fired over the crossbar from close range.
Neymar, Messi and Suarez all had shots on target in the opening seven minutes of action, but Man United stopper David de Gea was equal to all three strikes - producing a brilliant stop to prevent the latter from finding the bottom corner from a wide angle.
Messi fired a powerful effort just wide of De Gea's post in the 13th minute as Barcelona continued to threaten an opener, before Lukaku stung the palms of Jasper Cillessen down the other end of the field moments later.
Cillessen then had to fly across his goal to keep out a curving Pogba effort, before Mkhitaryan just missed the post with a low drive as a brilliant start to the pre-season friendly continued to excite the crowd.
Messi was in imperious form for Barcelona, and the Argentine had another sight of goal in the 27th minute - firing over the crossbar from just inside the Man United box - before De Gea had to be alert to keep out Neymar from a narrowing angle.
Barcelona finally made the breakthrough in the 31st minute, however, with the brilliant Neymar taking full advantage of a slip from full-back Antonio Valencia inside the United box to carefully place the ball into the bottom corner of the net.
Messi came close to making it 2-0 in the latter stages of the first period when he curled a beautiful free kick towards the top corner, but the Argentine's effort just missed the crossbar, before De Gea made a reaction save to prevent Luis Suarez's inventive volley finding the back of the net.
Mourinho introduced Eric Bailly, Marouane Fellaini, Matteo Darmian, Sergio Romero and Phil Jones at the interval, while Barcelona boss Ernesto Valverde made 10 changes ahead of the second period, with the likes of Gerard Pique, Andres Iniesta and Sergi Roberto entering the field for the Spanish giants.
The opening 15 minutes of the second half passed without any real action as both teams struggled to find space in the final third, although Barcelona's fresh legs were causing issues.
Andreas Pereira and Anthony Martial both came off the United bench for the final 30 minutes, and the latter curled one just over the Barcelona crossbar minutes after entering the field.
Barcelona might have doubled their lead in the 66th minute after substitute Paco Alcacer escaped the attentions of Bailly inside the United box, but Romero was on hand to make a brilliant save.
Man United were a threat down the other end, however, and Pereira brought a decent save from Cillessen 20 minutes from time as the 20-time English champions looked to level the scores.
Mourinho's side continued to push forward as they looked for a late leveller at the FedEx Field, and the Red Devils had a late penalty shout when Martial fired the ball at Denis Suarez, but Barcelona closed out the final stages to triumph in the International Champions Cup fixture.
Next up for Barcelona is the small matter of El Clasico against Real Madrid in the International Champions Cup on Saturday night, while Man United will now travel back to Europe as they prepare to face Valerenga in Norway on Sunday.