The lightly tried galloper has not been tested past 1200m since rising from rating 65 grade to the open handicap ranks, with seven wins from 10 starts.
Prince Oz is one part of a strong two-pronged attack Ridley has on tomorrow's listed Great Easter Stakes.
Prince Oz opened the second favourite for the race at $5, behind his stablemate He Kin Fly, who was at $4.60.
Those prices reflect Ridley's assessment that there is little between his pair's chances in the race, though he saidHe Kin Fly has the advantage of a proven record over 1400m.
The ex-Hong Kong galloper steps back up to that distance tomorrow after beating Prince Oz over 1200m in a minor event at Riccarton last month.
That gave He Kin Fly a hat-trick of victories after he scored back-to-back 1400m wins.
The first of those saw him win his first black-type race under the same circumstances he will race under tomorrow at Riccarton: 1400m under handicap conditions.
Prince Oz ran second to He Kin Fly in his 1200m victory in preparation for tomorrow's race.
Ridley said Prince Oz has come through that run and worked well.
The trainer said he would like to see a strong race pace for Prince Oz to show his best over 1400m.
A 1400m specialist looks one of the hardest horses for the Ridley-trained pair to beat tomorrow.
Kiwi Ida has never finished out of the first five placings, and continued that record with an emphatic last-start win at the Riverton Easter Carnival.
The topweight Disturbance and lightweight chance Moyrabella also bring excellent form to tomorrow's feature.
The Michael and Matthew Pitman stable have a strong hand in the race with in-form runners Elfee and Dynamic.
