"He has been a great horse for his owners and has won them more than a million dollars." Moriarty carried 57kg in the Railway (1600m), 1kg less than topweight The Cleaner.
He came from the back of the field on the turn to be beaten less than from the winner Elite Belle and a nose behind Balmont Girl.
Ahead of the barrier draw, Moriarty is at $4.60 with Elite Belle and Balmont Girl at $5.50 and $7.
As well as making sure his horses are placed where they can win, Waller also ensures they are ridden by the best jockeys he can find.
With Nash Rawiller suspended, Waller has attracted another Hong Kong rider, Douglas Whyte, to replace him. The 13-time Hong Kong champion, Whyte lost the title last season to Australian Zac Purton.
Whyte rode the Waller-trained Junoob in the Caulfield Cup in October when the Metropolitan winner finished seventh, 2 lengths from Japanese horse Admire Rakti.