The Demuro brothers capped a one-two in the first Classic race of the season as Cristian held off the older Mirco to win the Oka-sho aboard Ayusan on Sunday.
The 20-year-old Cristian rode seventh choice Ayusan to victory in 1 minute, 35.0 seconds over a mile for his first Grade 1 title in Japan.
Dubai World Cup winner Mirco's Red Oval, the second pick in a field of 18, finished a neck behind Ayusan in the first leg of the filly's triple crown. Fourteenth choice Princess Jack came in third another 2½ lengths back, just ahead of race favorite Kurofune Surprise.
"She's a very good horse," said Cristian, the leading jockey in Italy the last two seasons. "When I asked her to go she was very sharp. Red Oval passed me, but my horse came back one more time."
Asked of the stretch duel against his older brother, Cristian said, "It was a good fight. I know my teacher. He told me I did a good job. When we started, I saw that my horse was in very good condition and I tried for good position."