The win assured the Filipinos an outright berth in the FIBA World Cup in Spain next year.
Gilas initially went for a 9-7 lead, before Korea's shooters started connecting to take the first quarter, 19-15.
Jason Castro came up with a string of plays to tie the game 19-all, but the Koreans quashed the rally to regain the lead, 28-21.
The first half ended 39-36 with the Koreans ahead.
The Nationals fought back early in the third as Castro's back-to-back baskets had Gilas surging, 42-39.
LA Tenorio and Ranidel de Ocampo kept the offense going for the Nationals to make it 56-48.
Japeth Aguilar's slam helped Gilas to extend the lead to 65-56 going into the final period.
Korea began hitting its shots again and came within three points, 67-64. Gilas momentarilly halted the run, but the Koreans came back and grabbed the lead 74-73, 4 minutes left.
Jimmy Alapag and De Ocampo allowed Gilas to take a one-point breather, 78-77, going into the final 2 minutes.
Successive triples from De Ocampo and Alapag eventually allowed Gilas to take the 86-79 win.
The victory also allowed the Philippines to vindicate its past heartbreaking losses to Korea, which foiled the country's campaigns in the 2002 Asian Games and the 2011 FIBA-Asia Championship.
Gilas will face Iran in the FIBA Asia Championship title game Sunday.
Iran defeated Chinese Taipei, 79-60, in the other semifinal match.
source: www.abs-cbnnews.com
