Barbier played some fine shots down the ground and over the ring, batting with intent.
Shanks' solidity in defence and back-foot strength to force the ball through the offside was a feature of his innings.
Coastlands spinners Spencer Wills (four wickets for 19 runs) and Gus Tustin (3-22) bowled out and Darcy Collett took 1-16 in 5.3 overs.
Off-spinner Wills' skill lay in his pace variation while leg-spinner Tustin created doubt with the sliding delivery, hitting the timber twice.
Offie Collett ended Shanks' committed vigil with a return catch.
In response, Coastlands opening batsmen Utsav Kumar (54) and Kade Smit (21) put on 68 before the latter fell lbw to Poverty Bay's first-change paceman Bekko Page (1-24).
Kumar played some mighty shots to all points on the compass before being adjudged leg before to left-arm wrist-spinner Dylan Torrie (1-8 in five balls), operating over-the-wicket — the only bowler of his type at the tournament.
Coastlands second-drop Luke Scrimgeour pulled the only ball he faced for four and Coastlands ended the game at 104-2 in 14.5 overs.
Young swing bowler Taye McGuinness went without a scalp in three overs but asked as many questions of the batsmen as anyone else.
Poverty Bay fought hard. Having lost both Kelan Bryant and Nathan Trowell to injury earlier in the week, they plugged away manfully.
Counties-Manukau 265 all-out in 49.3 overs (Oscar Taylor 91, Rikesh Patel 46, Aryandeep Mann 31, Louis Anderson 27; Hunter Crowe 4-44, Benji Bell 3-32) beat Waikato Valley 205 all-out in 47.5 overs (Cameron O'Leary 58, Max Makeham 35, Jake Morey 20; James Kingham 3-43, Rikesh Patel 2-16, Hugo Harkness 2-20) by 60 runs.
Bay of Plenty Lakelands 224-6 in 40.1 overs (Ben Astwood 65, Cohen Stewart 52 not-out, Pieter Osborne 48; Hemanth Akula 2-35) beat Northern Districts Invitation 223 all-out in 48.5 overs (Hemanth Akula 96, Sebastian Heath 60; Ben Astwood 3-30, Samuel Lund 3-40, Andrew Friskney 2-42) by four wickets.
Hamilton 302-8 in 50 completed overs (Angus Henry 89, Lucky Reddy 42, Rohan Gosai 36, Daniel Kibby 33, Eli Parker 28, Liam Hayman 22; Lucas James 3-47, Cullen Hilton-Jones 3-55, Kieran McClintock 2-59) beat Northland 142 all-out in 36 overs (Nick Byles 42, Sanchit 17; Lucky Reddy 4-32, Liam Hayman 3-24) by 160 runs.
Bay of Plenty Coastlands 104-2 in 14.5 overs (Utsav Kumar 54, Kade Smit 21; Dylan Torrie 1-8, Bekko Page 1-24) beat Poverty Bay 101 all-out in 37.3 overs (Alex Shanks 23; Spencer Wills 4-19, Gus Tustin 3-22, Darcy Collett 1-16) by 8 wickets.