The 23-year-old netter from Vienna pulled off a 4-6, 6-0, 6-2 upset over top seed and worlds No. 156 Yoon Yong-il of Korea to earn $1,950 in cash and 12 ATP points.
"I didnt play bad in the first set, I just lost so much energy. It was good at the start but I was very eager to win and made too many mistakes," said Mlynarik, who led 4-2 in the first set before Yoon revved up his game to prevail.
Mlynarik, who had title victories in the Czech Republic and South Africa this year, played slower in the second set which proved effective as the Korean tried but failed to adjust with his game.
Mlynarik kept his level of performance in the third frame, breaking Yoons serve on the fifth game for a 4-1 lead.
Yoon regained his form, breaking Mlynarik on the sixth game at 2-4. But the Austrian played steadier and won the next two games to wrap up the match in 1 hour, 34 minutes.
"I had a good performance since September and it made me quite confident," said Mlynarik, who scored a hard-earned 7-6 (5), 7-6 (5) victory over fifth seed South African Donovan September in the quarterfinals of this event supported by the ITF Grand Slam Development Fund, PSC, Wilson Ball, Manila Midtown Hotel and Viva Mineral Water.
Mlynarik hopes to do well in the second leg which will start today. "I think that I can play good but my chances of reaching the final again will depend on who Ill be playing with and Ill be fit."