CONMEBOL has appointed Chilean referee Piero Maza to lead the first leg between Boca and Vasco da Gama, his third knockout appointment this season.
Maza previously oversaw Boca’s home wins over Deportivo Recoleta and San Pablo, but he also presided over their painful 2025 Libertadores exit at the hands of Alianza Lima.
Maza’s history with the Xeneize
His debut with Boca came on May 27, 2022, when the Argentine side edged Deportivo Cali 1‑0 at La Bombonera to reach the Libertadores round of 16.
In 2024 Maza refereed Boca’s Sudamericana opener against Nacional Potosí in Bolivia, a goalless draw where he awarded a penalty that Darío Benedetto missed.
The latest knockout clash he handled was the 2025 Libertadores second stage, where Boca won the return 2‑1 but lost the tie on penalties after a 2‑2 aggregate with Alianza Lima.
Chile’s referee trio for the semi
During the recent tie with Recoleta, Maza sent off Wilfrido Báez before halftime and Dairon Mosquera in the second half, and bizarrely had Boca take the kickoff twice at Tomás Adolfo Ducó.
For the Vasco da Gama leg, his assistants will be José Retamal and Carlos Poblete, with Mathias Riquelme as fourth official and José Cabero and Juan Serrano handling VAR. In my view, Maza’s experience makes him a safe pick.