City's Zac Khawaja smashed a century in the opening round of the Lion Red Cup at Kensington Park, dashing Onerahi's hopes of starting off from where they left off last year.
Khawaja scored 132 from 141 balls, which included a whopping 15 fours and four sixes, as City combined to set Onerahi 300 from their 50-overs - and eventually win by 174 runs.
Opening the batting, Khawaja and Joey Yovich put on 51 before Yovich (29 off 20) lost his wicket to Dillon Lees on Saturday.
However, it was the second wicket partnership between Khawaja and captain Ian Page which did the damage. Page and Khawaja progressed the score through to 169 before Page was removed for 46 in the 32nd over.
A tidy 32 off 30 by Steve Morris and a quick-fire 23 off 15 from Kieran Nelson helped push City through to 299 for 8 after their full complement.