The 'friendly' certainly had some watch value in the first period, with great chances from Romelu Lukaku, Luis Suarez, Lionel Messi, Paul Pogba and Marcus Rashford but the score remained goalless until Neymar’s strike in the 31st minute.
The second half certainly lacked entertainment and chances, with Anthony Martial and Paco Alcácer going close but not enough to change United tasting defeat for the first time in pre-season.
Nothing friendly about it
It had been an excellent tour of America for United having won all four of their matches ahead of their clash with the Catalan giants. A win would have secured them the International Champions Cup title but Barca were certainly not proving a pushover as both sides had excellent chances early on.
United could have had the lead inside two minutes as Rashford played an excellent ball in from the right which swept across the face of goal. Lukaku was running in but a minimal bounce worked against him as he sent it well wide. Fortunately, for his pride, the flag had been raised on the far side.
Barca then had their own spell of dominance and were only denied by the excellence of David De Gea and the woodwork, their first chance came in the tenth minute as Suarez found himself in a tight spot.
The Uruguayan did well to make some space on the left of the area, his effort was low and curling but De Gea did brilliantly to tip it wide.
Two minutes later it was then the turn of Messi. He received the ball on the edge of the area, the Argentine then burst into life to push his way through defenders to the edge of the area and let rip, but it could only clip the post on its way behind.
It was end-to-end stuff at the FedExStadium and it was once again the turn of United to try and make an early breakthrough. Pogba was dispossessed some distance from goal but the bounce worked in his favour as he decided to hit it on the half-volley with exquisite technique and forced Jasper Cillessen to push it wide.
Rashford and his pace were proving hard to deal with it early on and he was gifted a good chance in the 17th minute. He did well to regain possession and create the one-on-one situation after squeezing past one defender. The angle was against Rashford at the near post, and Cillssen did well to block the effort with his body.
That man once again
Neymar is certainly the most talked about name in world football right now, not only for his form so far in pre-season but his apparent big-money move to Paris Saint-Germain. The Brazilian added another to the speculation, simply by scoring again, in the 31st-minute, the game's only goal.
It was a devastating counter attack from the Catalan club through Messi as he drove at the United defence and played the through ball looking for Neymar. Antonio Valencia nipped in front but his tumble opened it up for Neymar. The winger did well with the turn to evade the ensuing penalty area scramble, before coolly slotting past De Gea into the bottom corner.
Neymar could have easily made it his second of the night with four minutes of the half to play, as the winger was alive to the quick free-kick. The set piece was deflected into the air but Neymar had his eye on it all the way as he went for the spectacular overhead kick, but De Gea produced an excellent save to deny him.
Falling flat on its face
The second half fell very flat very early on as it failed to live up to what the first had to offer. Both sides still had one decent opportunity each to try and kick the game into life once again.
The first came from United in the 66th minute as the substitute Martial picked the ball up on the left-hand side of the area, the Frenchman decided to curl it but it went a yard just over the target.
Barca fired back just two minutes as Sergio Romero was forced into action to keep his side in the contest. A long ball got the better of Eric Bailly and allowed Alcácer to break free and allow him through on goal but Romero did brilliantly get down low and tip it away.