Slack defending dictated the course of the game with Alresford capitalising after Lucas McCartney had provided the assist for an unmarked Sam Burt to find the empty net.
An unsettled Joe Coombes, standing in for injured Bash goalkeeper Joe Prodomo, added to the indecisiveness by punching a 26th-minute corner into his own net for the visitors' second.
Bashley frontrunners Kabba Jack, Dan Munday and Harry McGrath were actively engaged but were unable to penetrate a super-efficient Town backline.
The visitors stopped any Bash revival by attacking from the start of the second half with Tom Sands missing a sitter in the first minute.
This respite was short-lived as Scott Munro gratefully received a defence-splitting pass from Sands to make it 3-0 just minutes later.
Bash's agony continued when a poorly-defended corner allowed substitute Aaron Blaxall to score with ease.
McGrath finished with aplomb to reduce the arrears following good work by Jack and Jesse Gould but Alresford completed the scoring when Blaxall was left free to score his second and the visitors' fifth in the final minute.
Bashley: Coombes, Dathan, Aimson, Brailey, Rolls, Lucas, McGrath, Slade, Jack, Munday, Gould. Used subs: Morris, Bada, Vining.
- Poppies took a giant step towards preserving their Wessex Premier status after battling out a 0-0 draw with Team Solent at Victoria Park.
A share of the spoils left them five points clear of the drop zone with three games remaining, the first of which is at Horndean on Saturday.
- Meanwhile, Wessex Premier strugglers Cowes Sports have parted company with manager Richie Woodburn.
His departure followed their 6-0 defeat by Portland United on Saturday.
Ian Potts, Woodburn's assistant, will take the reins on a caretaker basis until the end of the season.
Potts won his first match in charge when they beat Brockenhurst 2-0 at Westwood Park thanks to goals from John McKie and Fin Phillips.