Sorry for destroying the thread. His first PtP ride was on March 28th 1998 when he partnered Mickthecutaway at Naas. I think you can call this his first chase ride under rules.
Source: p2p.ie
However according to the RP site the first ride he had on Mickthecutaway was on February 5th 1998 and finished third on him.
Source: racingpost.com
Whoever is right, I don’t know.
Just move on to the next question….