Yiu secured champion trainer honours at the final meeting of the local season at Happy Valley on Wednesday and while thrilled to achieve a career goal, he took the milestone in his stride.
"I've been in horseracing all my life - winning, losing, it happens every meeting so I take it very easily," Yiu told the Hong Kong Jockey Club.
Yiu has been involved in racing for almost 50 years, starting as an apprentice jockey in 1972.
He was not expected to challenge for the Hong Kong trainers' title this season but when it became apparent he was capable of figuring, he chased it earnestly.
"I just put my head down, kept working and kept focusing," Yiu said.
"When I saw they weren't catching up, it's a once in a lifetime chance, so I went for it."
A treble at Sha Tin on Sunday took Yiu to 67 wins for the season, four clear of Tony Cruz.
Cruz narrowed the gap to three with a victory at Happy Valley on Wednesday and while Yui was unable to add to his tally, his lead was enough to claim his first premiership crown.
Australian Zac Purton clinched his fourth Hong Kong jockeys' title at the penultimate meeting of the season on Sunday.