United 2nd XI's Ritesh Verma (4-34) got a couple of those key scalps while also helping clean up the tail as the last five wickets fell for 33 runs.
The 1st XI pressured their clubmates throughout the run chase until the lower order was exposed, dismissed for 133.
Their best hopes had been openers Allister Bostock (18), Zeb Small (23) and top-order batsman Alan Kenny (26).
However, Walker (3-13) removed the top order, and then when six runs were needed per over in the last 12 overs, veteran Robbie Power (5-36) got the tail out to catches off his spinners.
In the other round-robin games, Matt Burke Engineering Marton Saracens just got home by one wicket against Wicket Warriors Whanganui at Centennial Park, while Wanganui Vet Services Marist picked up a default win over Whanganui Collegiate Senior Black.
Results, January 15
Rep Weekend Pro 40, round 5
Pool 1
Wicket Warriors Whanganui 132 (S Skreekumar 27, A Pillai 22no; S Singh 3-25, B Cunningham 2-19, B Galpin 2-21, F Lane 2-29) lost to Matt Burke Engineering Marton Saracens 133-9 (A Pond 25, A Spence 20; V Chacko 5-22, S Skreekumar 2-14, L Varghese 2-30) by one wicket.
Wanganui Vet Services Marist bt Whanganui Collegiate Senior Black by default.
Pool 2
Wanganui Renegades bt Whanganui Collegiate Senior Blue by default
Tech Old Boys vs Wanganui United 3rds
Final
Property Brokers United 1st XI 190 (S Badger 45, T Lance 33, B Walker 32, S Holloway 21; R Verma 4-34) bt Treadwell Gordon United 2nd XI 133 (A Kenny 26, Z Small 23; R Power 5-36, B Walker 3-13) by 58 runs.