Ousting 15th seed Nick van den Berg Wednesday, the short, stocky young pool master claimed an even bigger victim in Lee, losing finalist last year and semifinalist the previous year back home.
De Luna, 22, distinguished himself as the first Filipino to reach the Final 32 and the Last 16. The RP contingent, however, lost another premier bet in Lee Van Corteza, who bowed to Spains David Alcaide, 8-10.
"That was a big win. The old man has complete artillery in his arsenal. I upset him," said De Luna of his conquest, which assured him of $4,500 in prize.
"Im getting closer to the championship and I feel better now, feeling relieved of the pressure I felt in facing this Taiwanese. I saw him play in a money game Wednesday night and I was impressed. In fact, I lost sleep (thinking of the match)," De Luna added.
De Luna drew several deep breaths before taking the match point. Then he smiled amid cheers from the crowd when he eventually closed out the match.
With a precarious 9-8 lead, De Luna got the opportunity to finish the match on the 18th rack as Lee scratched while doing a safety.
He raced to a 3-0 lead but went through anxious moments when he fell behind at 4-6.
From a 7-all deadlock, De Luna regained control when Lee committed costly errors in the next two racks.
De Luna also blundered on a vital shot as Lee closed in at 8-9. But the Taiwanese scratched the cue ball in the ensuing play that drew loud cheers from the home crowd and De Luna took care of business from there.
"Hes so good but I had a big edge with the crowd getting involved in the match," said De Luna.
Corteza also had the crowd behind him but suffered lapses in his play that spelled disaster in his showdown with Alcaide.
Errors by Corteza in the 16th and 18th racks paved the way for Alcaides victory, which matched his Final 16 finish in the 2002 Cardiff WPC.
"Filipinos are respected so much in the billiard world. To beat them, you have to play your best," said Alcaide, the 27-year-old Malaga, Spain native who is ranked No. 10 in Europe.
Reigning champion Wu Chia-ching topped fellow Taiwanese Wang Hung-hsiang, 10-3, while Fu Che Wei whipped Chao Fong-pang, 10-8, in another all-Taiwanese Round of 32 battle.
Pat Holtz of Scotland tripped English Kevin Uzzell, 10-6, in the other match completed at press time.
Efren Reyes, Ronato Alcano, Marlon Manalo, Rudy Morta, Rodolfo Luat and Jherome Peña were the other Filipinos with a shot at the Final 16.