Blathwayt's current preparation was opened with a first-up victory over a mile at Hastings before he finished third under 60.5kg at Otaki where he gave the winner nine kilos and the runner-up 5.5kg.
The son of Colombia dropped down the handicap to 53.5kg at Awapuni and, in the hands of Danielle Johnson for the first time, he travelled comfortably midfield on the rails.
Blathwayt was off the fence at the right time and he finished off powerfully in the straight for the seventh win of his 22-start career.
Thorn Prince also got home strongly to take second off the topweight Authentic Paddy, who made all the running and had looked a winning hope when he shot clear into the straight.
King Kamada and Benzini finished fourth and fifth respectively and did their New Zealand Cup chances no harm.