Asato, who rolled the tournament's second 300 in the eighth and final game of earlier the Round 2 finals, advanced into the Stepladder finals as topseed. The Japanese narrowly lost the first match, 214-217 to challenger, Lee Tak Man of Macau forcing a sudden-death decider.
The topseed got off to a sizzling start rolling seven consecutive strikes in the deciding match while Lee responded with a double in his first two frames and rolled four consecutive strikes from frames six to narrow the advantage.
But the Japanese kept his composure to win the match, 259-236 and bagged the title. Lee, who led the earlier round only to concede top spot to Asato's perfect game, dispatched two Hong Kong nationals, third-seed Michael Mak and Otto Leung, 261-212-236 in the semi-finals to face Asato in the final.
Leung, who squeezed into the stepladder finals in sixth, edged two compatriots, fourth-seed Lau Kwun Ho and fifth-seed Ivan Tse, 237-235-232 in a closely fought first stepladder match. The champion picked up MOP$70,000 (approx. US$8,700) while Lee settled for MOP$30,000 as first runner-up.