The 24-year-old Marcial made it after he hurdled Ashish Kumar of India via a split decision victory in their middleweight division semifinals late Tuesday evening in the 2020 Asia/Oceania boxing qualifying tournament in Amman, Jordan.
The 5'8" Marcial, the only Filipino boxer so far to book a ticket to the 2020 Tokyo Olympics, led on points in the first round, after he countered Kumar's long lefts with a right hook to the chin and a flurry of left crosses as well.
It was a rugged contest in the second round, with a chopping right from Kumar finding its mark, but Marcial still took the second round.
Marcial got a standing eight-count following a left jab from Kumar, but the Filipino recovered by sending Kumar aback with his counters in the third round.
This put Marcial up against Kazakh Abilkhan Amankul in the finals.
Amankul emerged as Marcial's finals rival when he also won by split decision over Tanglatihan Erbieke of China.
In the first round, Amankul connected with a left cross, and with Erbieke still landing with counter shots. But the Kazakh still led on points, 3-2.
Amankul took round two, 3-2, after weathering more counters from his Chinese foe.
In the third, a cracking right-left from Amankul, followed by a right jab allowed him to put Erbieke off his balance.
Meanwhile, men's flyweight (48-52 kgs) Carlo Paalam will try to seek another shot at an Olympic berth when he battles Bibossinov Saken of Kazakh in a consolation round boxoff.
Women's flyweight (48-51 kgs) Irish Magno will also try to keep her chances afloat when she meets Qosimova in Sumaiya (Tajikistan) in another boxoff.