The 25-year-old Brazilian superstar is at the centre of frenzied speculation linking him to a gargantuan, world record 222-million-euro ($256.8 million) transfer to Paris Saint- Germain.
Neymar had kept the guessing game about his future bubbling away after posting a picture of himself looking pensive on Instagram on Friday.
But there was little to suggest that the charismatic striker is overwhelmed by the transfer saga as he produced a bewitching performance in front of a sell-out 82,104 crowd at the MetLife Stadium in New Jersey.
At the other end, Mario Mandzukic might have given Juve the lead on 14 minutes but his header from a Stefano Sturaro cross went wide.
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The Italians were made to rue Mandzukic's profligacy a minute later when Neymar fired the Catalans into the lead, playing a clever one-two with Paco Alcacer and drilling his finish past Gianluigi Buffon.
Neymar might have had a hat-trick three minutes from half-time, when Messi floated a delightful pass in behind the Juve defence for the Brazilian.
Buffon on this occasion was equal to the challenge however and blocked safely. Barcelona rang the changes at half-time, withdrawing all but two of their starting line-up, Neymar exiting for Sergi Roberto and Arda Turan replacing Messi.
Juventus also made a raft of substitutions which led to the introduction of Paulo Dybala, Gonzalo Higuain and Douglas Costa amongst others.
From the ensuing setpiece, Giorgio Chiellini nodded home Dybala's cross to make it 2-1. However it was Barcelona who finished the stronger of the two sides, with Luis Suarez repeatedly threatening to extend the Spanish side's lead.