In an astrological text of which I so far have only a single manuscript, I recently came across an expression which may be in need of emendation or may just be an idiom I haven't seen before:

aśvadvayasya madhye ko vijayī lagnabhāji horeśe |
yaḥ prathamaṃ hṛdaye ’bhūt tasya jayo ’nyasya vaktavyaḥ ||

'Out of two horses, which will win? If the ruler of the hour occupies the ascendant, the one that first occurred in the [querent's] heart should be predicted to win over the other (?).'

It is the double genitive in tasya jayaḥ anyasya that I am uncertain about. Can anyone confirm (or deny) that this idiom exists?

Best wishes,
Martin Gansten