The highly rated 19-year-old, who has represented Serbia at under-17 level, also featured in a defensive midfield position last season as Jedinstvo finished as runners-up in the second tier to clinch promotion to the Serbian Super Liga.
Born in Novi Sad, north west of Serbian capital Belgrade, Pivaš began his career with Austrian regional sides UFC Siezenheim and SV Grödig before returning to his native country with Jedinstvo in 2023.
Pivaš said: “It’s absolutely unbelievable to join such a big club like Newcastle United and I cannot wait to get started. I see the project of the club and it looks great which helped convince me to sign for Newcastle.
“I see the young players have developed very well here and I would like to do the same - to develop and get into Newcastle's first team. I’m very excited and I can’t wait to begin.”