But the other Filipino jin, Donald Geisler III, lost a close encounter with former world champion Bahri Tanrikulu of Turkey, waging an amazing comeback and leading in the last 32 seconds before bowing out on superiority.
Rivero leaned on a big fighting heart and a tenacious stand despite a shaky start and a bruised left thigh to beat former world silver medalist Vanina Beron Sanchez of Argentina on superiority after a 10-all draw in the first round of the minus 67 kg. class.
The sophomore student at the Angelicum School back home, at 16 one of the youngest in the field, reported 40 minutes later to outclass the Netherlands’ Charmie Sobers, a quarterfinalist in the Cheju, Korea world event in 2001, with a 10-4 decision in the quarterfinals.
That sent the 5-foot-8 Rivero into the semifinals later in the day in a tough outing against Greece’s Elizavet Mystakidou and a raucous foot-stomping, flag-waving sellout homecrowd.
If the Filipina jin pulls off a stirring triumph over the home favorite, ranked third in the world last year, she will move into the final possibly against China’s world champion Wei Lou, and assured the Philippines of a silver medal.
"I believe I played well, it was an important victory. Now I must look at my strategy for the game against Mystakidou," she said.
A loss would reduce her bid to a crack at the bronze from repechage, the loser’s side. Unlike in Olympic boxing, only one bronze is offered in all four weight divisions in taekwondo.
"She fought well, wasn’t scared and in high spirits.
In the second match, she loosened up and became more confident," said Robert Aventajado, president of the Philippine Taekwondo Association.
The first match, against Sanchez, was fraught with drama. The Pinay teener trailed by two points in the first round, 2-4, levelled the score at 4-all but fell behind anew at the end of the second round, 5-7, as Sanchez scored on two defensive kicks.
But Rivero, who has been carrying the fight by putting the pressure on the 25-year-old Argentine, fired three offensive kicks in the first two minutes of the final round while Sanchez countered with two points for an eight-all deadock with one minute and 10 seconds left in the contest.
The two scored simultaneously for 9-all and Sanchez moved on the brink of victory with a clear point, 10-9. As the time wound down to the last 28 seconds, Rivero sought for an opening and delivered an axe kick near the end of the round to force a 10-all score. She later won on superiority.
"It was an exciting match and she became very confident in the last round," said Korean Grandmaster Hong Song Chun, the PTA vice-president.
It was a different Rivero that climbed the plush elevated blue mat in the quarterfinals.
The Hanoi Southeast Asian Games gold medallist was all charged up and brimming with confidence as she raced from a 2-all tie in the first round with three offensive kicks and one offensive thrust while Sobers failed to score a point, 6-2.
Then she dominated the 31-year-old Dutch jin with five more points to end the contest at 10-4. As the buzzer sounded signalling the end of the bout, Rivero raised her hand and punched the air in triumph as she walked to Korean coach Tae Hyung Kim.
"She’s a bit tense in the first match but we monitored the fighting style of Sobers and we strategize our own game, waiting for her to move first because the opponent was aggressive. Maganda ang naging resulta," said national coach Jesus Morales III.
It was a bitter defeat for the veteran Geisler who trailed for the first two rounds, losing momentum the moment Tanrikulu scored with a hard kick to the face 14 seconds at the close of the first setto, 1-4.
The 23-year-old Turk world titlist made it 7-2 with sharp and slashing kicks and looked headed for the win until the 25-year-old Geisler pivoted and launched a turning long kick to the face that stunned Tanrikulu to make it 5-7.
The two-time Filipino Olympian then seized the lead 8-7. A series of exchanges ensued before the Turk forced a 9-all deadlock with clear two points in the end, 11-9, negating two points on warning penalties.
The judges didn’t waste time to break the tiebreak and gave the decision on superiority for the aggressive and talented Turk.
Geisler may contend for the bronze if Tanrikulu reaches the final late tonight.