The Portuguese club want to reward the 20-year-old's progress and protect one of their most promising attacking players from growing interest elsewhere. According to A Bola, negotiations have advanced over his salary, the length of a new agreement and a signing bonus, with only the payment schedule still to be settled.
Prestianni is currently contracted to Benfica until 2029, but the club are looking to extend that commitment. The reported proposal would take his deal beyond its existing expiry date and recognise the impact he has made since establishing himself in the first team.
The outstanding issue concerns when the player would receive the bonus attached to the new contract. Prestianni is understood to want the payment immediately, whereas Benfica would prefer to make it at the end of the season. The difference has not prevented progress on the other terms, but it remains the final point to resolve before the agreement can be completed.
The timing is significant because the winger's performances have attracted attention beyond Portugal. Paris Saint-Germain and Bayern Munich have both been linked with an interest, according to the reports cited by Fussballtransfers.
Benfica therefore have an incentive to reach an agreement before the transfer market creates further uncertainty around his future.
Prestianni has enjoyed an outstanding campaign, becoming one of the more prominent young attacking players in the Portuguese league. His form has strengthened his position at the Estádio da Luz and increased the club's determination to retain him.
There is, however, a distinction between an agreement in principle and a completed renewal. While the reported progress over salary and duration suggests the parties are close, the bonus arrangement still needs to be resolved and the new contract signed.
Benfica have already been working to extend or improve the terms of several important players as they seek to preserve the core of their squad. Retaining Prestianni would fit that wider approach, particularly with clubs elsewhere in Europe monitoring his development.
For now, the negotiations appear advanced, but the final payment detail remains between the player and the club.