An injury-time strike from sub Stephen Dobbie secured Albion their first win in eight games.
It’s a result that’s been a long time coming but one that was richly deserved after Albion were encamped in the Posh half for long periods of the game.
Dobbie certainly made a big impression after he came on as a second-half sub for Andrew Crofts and he won’t forget his first Albion goal in a hurry.
With the referee signalling four minutes of injury time, Albion continued pressing for the winner. It duly arrived when Ashley Barnes poked a ball into the striker’s path, via a deflection off Will Hoskins, and the former Swansea man made no mistake from close range.
Such a breathtaking climax would have been hard to predict after a tepid opening half.
Indeed, following the thrills and spills of Friday night’s encounter against Leeds, the opening stages against the division’s third-from-bottom club were flat in comparison.
It took until the 14th minute before either side had an effort at goal, with Posh’s Grant McCann volleying wide.
It at least spurred Albion into action and in the very next attack Will Buckley crossed from the by-line only for Crofts to drill his effort over the bar.
Albion started to get more of a foothold in the game, with Bruno afforded plenty of space down the right flank.
He first teed up Buckley for a volley which was deflected wide and then sent in an inviting cross for Craig Mackail-Smith, which the former Posh striker headed straight at keeper Robert Olejnik.
Peterborough looked a threat on the break with ex-Crawley striker Tyrone Barnett heading over on the half-hour mark, while Gordon Greer was forced to head a Mark Little cross away for a corner.
Lewis Dunk, making his first League start of the season in place of the injured Adam El-Abd
, looked assured alongside Greer and a couple of timely interceptions would have further boosted his confidence.
Mackail-Smith again went close with a header from Andrea Orlandi’s inswinging free-kick, while the Spaniard drilled an effort wide but the 0-0 scoreline was a fair reflection of a rather subdued half of football.
Albion certainly lifted their game after the re-start with Barnes’s curling effort pushed away by Olejnik for a corner, while Buckley’s cross-cum-shot drifted narrowly wide of the keeper’s right-hand upright.
It set the tone for the half as Albion found themselves flooding the Posh half in search of that elusive opener.
Buckley stung the keeper’s hands with a rasping 20-yard drive while Orlandi also hit the foot of Olejnik’s upright from a similar distance.
Mackail-Smith then flashed a header over the bar before dragging an effort wide but with the scores still goalless, Gus Poyet brought on Dobbie – which proved to be an inspired substitution.
Wayne Bridge was the next player to test Olejnik drilling a low effort inches over the bar while Dobbie also had an effort beaten away following a well-worked free-kick involving Orlandi.
Hoskins entered the fray for his first appearance of the season, replacing Mackail-Smith, and although it looked like recent history repeating itself with Albion dominating possession and chances without taking the points, up stepped Dobbie to lift the clouds which had hung over the Amex for too long.