The match, played at Barca's Camp Nou, featured the likes of Rivaldo, Edgar Davids, Dwight Yorke and Karel Poborsky, but it was the 37-year-old former Brazil superstar who grabbed the spotlight.
In typical fashion, Ronaldinho's dazzling array of tricks and flicks were the talking points of the contest, including a nutmeg through Jesper Blomqvist's legs that caused the Swede to fall to the pitch.
The move made the crowd buzz, but even current United star Anthony Martial felt the need to take to social media to register his appreciation.
The best @10Ronaldinho— Anthony Martial (@AnthonyMartial) June 30, 2017
Despite being on the wrong end of Ronaldinho's trickery, Blomqvist's day wasn't a complete embarrassment as the Swede was among the goalscorers in the United triumph. Joining Blomqvist on the Red Devils' scoresheet were Yorke and Poborsky, while Frederic Dehu scored the lone Barca goal.
While Ronaldinho did not get a goal for himself, he was still named Man of the Match. The two sides will meet again at Old Trafford in September.