Clifton wicketkeeper Te Pouakai Brown's 33 from 51 balls included four fours and the only six in the game.
Campion and Brown's partnership of 60 and Campion's third-wicket stand of 62 with Noah Lee-Joe (9) were key in Clifton's posting 160-5.
Poverty Bay firebrand Archer Allen and the skilful, capable Finn Robertson both took 1-13 from four overs with the new ball.
Robertson also took two superb catches — at fly slip to dismiss Brown off Allen's bowling, and at cover to snare Lee-Joe off the bowling of flighty leg-spinner Liam Spence (1-13 from three overs).
Clifton coach Duncan Campion was moved to remark on the thoughtful leadership of 'keeper-cum-leggie Charlie Castles, and the role that Poverty Bay's spinners — Spence, his fellow leggies Castles and Harvey Reynolds (1-23 from four overs) and off-spinner Ted Gillies — played to rein in the hosts' strokemakers.
The Bay were bowled out for 132 in 33.2 overs, Reynolds (9) and Josh Levy (26) putting up 24 as an opening pair.
Levy made the Poverty Bay team's highest individual score. He times the ball sweetly and hits it with a fair amount of power.
Robbie Newlands, batting at No.7, played a fine knock for 17 and is an all-rounder of great promise in a handy side.
Clifton medium-pace bowlers George Matthews (2-11) and Jack Bagshaw (2-12) were the most successful of the home side's bowlers.
Campion senior was impressed by the batsmanship of Castles (16 runs).
The Bay had two chances to impress in 30-over play on the artificial wicket on Frimley Park 1 today, against Johnsonville this morning and Upper Hutt on the same pitch this afternoon.