A six-time national champion, Antonio emerged from the nine-round, Swiss system tournament unbeaten with 7.5 points, highlighted by a string of six straight victories starting from the opening round.
Although he wound up tied with Australian Grandmaster Ian Rogers, who was the highest rated player in the event with a FIDE rating of 2582, Antonio kept his crown for the second year in a row on higher tiebreak points.
It was a good outing for the for the Filipino woodpushers with GM Bong Villamayor finishing in a tie for third-fourth places with Irish GM Colm Daly with seven points each.
International Master Nelson Mariano, who is chasing his third and last GM norm, also made his countrymen proud by winding up in a deadlock for fourth-sixth with 6.5 points.
Mariano, who topped the side event blitz tournament by winning eight-of-nine matches in round robin play, was tied with Australian FIDE master Tim Reilly and Myanmar’s Wyn Zaw Thun.
Pinoy chesser Dante Ibaryu garnered the best non-Fide player honors by finishing in a tie for eighth-15th with six points.
"This was a much tougher tournament with the presence of five GMs, including Ian Rogers, who was once a super GM. Last year I was seeded second but last week I was seeded fourth," said Antonio.
"This also proves that contrary to what my critics say, I am far from being over the hill," added Antonio, who also earned FIDE rating points expected to boost his current 2523 rating.
His latest conquest was a brilliant followup to playing key roles in the last two local tournaments that he saw action in where his teams emerged the champion.
Antonio played solidly on board 2 as Tagaytay City captured the Asian Cities Chess Championship in March then powered the Tagaytay-Cavite squad to the championship in the Inter-Province province tournament a month later.