The 20-year-old Tierro, currently the country’s No. 1, overpowered Mario Sabas, 6-1, 6-0, in 40 minutes, while Arcilla trounced Miguel Narvaez, 6-0, 6-3.
Defending champion Chung Hee Seok demolished Jaime Solon, 6-2, 6-0, to likewise advance, but found himself pitted against compatriot Hee Sung Chung, who booted out Michael Basco, 6-3, 6-0.
Seok, 30, ran away with the PCA Open crown last year in the absence of the 6-foot Tierro.
"I saw him play and I think he’s okay but I will be ready ," said Tierro.
Arcilla is also ready to face the Koreans.
"I’m not worried about them, I think I’m prepared to face them this year," said Arcilla who bowed to Seok in the semis last year.
But first, Arcilla will have to hurdle Rolando Ruel Jr., who outlasted Rocky Paglalunan, 6-1, 6-4, in this tournament sponsored by Solar Sports, Accel, PVL Restaurant-Little Lawrence, Philippine STAR, Sun Village, Las Palmas, Powerade, Coca-Cola, Stronghold Insurance, San Miguel Brewery, Maresa Creative Group, Cel Consuledator, PMS Ship Agency, MILS, Equitable-PCI, Burlington, Dunlop, Pixel Project and Inquirer.
Semi-retired Adelo Abadia also marched to the next round after defeating Elbert Anasta, 6-1, 6-7 (2), 6-2. But the veteran Davis Cupper will have his hands full against Tierro in today’s match after losing twice to the young tennis star early this year.
Third seed Bum Seo Yung hurdled Nico Riego de Dios, 6-4, 6-1, to set a duel against eighth seed Alexander Lazaro, a 6-2, 0-6, 6-3 victor over Korean Hoon Seung Oh.
In the doubles competitions, top seed Czarina Mae Arevalo and Jennifer Saret routed Joanne Bibal and May Herrera, 6-0, 6-0, to barge into the quarterfinals.
Also winning their matches were Rina Caniza and Anni dela Pena, Karen Reyes and Anna Songco, sisters Bien and Bambi Zoleta, Ivy De Castro and Alyssa Labay and Arra Micayabas and Aileen Rogan.