David Sutherland (115-113) and Nathan Palmer (116-112) both scored it for Malajika, as the South African put a sluggish start behind him to upset the home favorite and claim championship gold.

Juan Carlos Pelayo's 115-113 Tsuboi score was deemed most accurate for many observers.

The 30-year-old former amateur standout gave rounds away by virtue of minimal head movement at distance, as well as wading forward into range without a tactic or sustained attacks in mind. That gave Malajika (18-2, 12 KOs) licence to connect on pit-pat shots and whenever they came close, a head clash or rough-housing seemed likely.

Tsuboi (3-1, 2 KOs) didn't seem to really advance past third gear for sustained periods, a burst or two of combination punching besides. A series of cuts, one quickly cleaned up after the first stanza and two more deeper abrasions in the middle rounds didn't help sharpen Tokyo resident's fight management in his maiden 12-round bout.

He led on two of the scorecards and the third was drawn through eight. Rather than step on the accelerator, the roles reversed and Malajika was the aggressor - especially in the penultimate frame.

Ryusei Matsumoto began promisingly and finished strong, but didn't have matters all his own way in the main card opener. He earned a 12-round points win (115-113, 116-112, 118-110) against a game Russell Acosta, as the Mexican clicked into gear in the middle rounds after being hurt by body shots and opting to deliver some of his own.

They exchanged furiously in the pocket and it was an exciting, ebb-and-flow battle between two quality strawweights aware the winner would be elevated to full titleholder once Oscar Collazo returns from injury.