A record second wicket stand and a towering 182 from Bangladesh A captain Monimul Haque was too much for the Ireland Wolves, who lost the fourth one-day game to trail 2-1 in the series with one to play.
A century from captain Andrew Balbirnie and a quick 50 from Simi Singh actually had the Wolves in front after 40 overs, but while Bangladesh thumped 127 off the last 10 overs, the hosts lost three wickets in five balls with the total on 279 and finished 85 runs short.
A belter of a Milverton pitch and a short boundary saw almost 700 runs scored, but the difference in the teams was the stark contrast in the number of four-balls bowled. While Bangladesh bowlers conceded 32, their batsmen hit 51 as the Wolves failed to find a consistent length.
It was not the pitch to bowl short on as all but Andy McBrine found out, his figures of 1-45 from 10 overs an oasis of respectability among the final analysis.
The other five bowlers conceded at least eight runs an over, including George Dockrell, playing his first game of the series.
Only three of them took wickets, with the only way they looked like getting the classy Monimul out was via a run-out - and so it proved, a throw from Simi Singh ending his innings in the 45th over, just 18 runs short of his own 200; from 133 balls, he hit 27 fours and three sixes.
His partnership of 210 with Zakir Hasan was the highest for the second wicket against an Ireland A side and just 11 short of the List A record by Gloucestershire at Castle Avenue in 1996.
With Mohammad Mithun finishing 87 not out from 51 balls, and hitting 14 fours and two sixes, it was carnage at the end, a scenario which the Wolves were always unlike to repeat.
James McCollum looked good for 14 overs, and Stuart Thompson likewise for the next 11, but 40s will not win matches, and an arm ball from the slow left armer accounted for McCollum, while Thompson holed out to mid-wicket.
Balbirnie brought up his century from 105 balls with 13 fours, but he was dismissed immediately afterwards, driving straight to mid-off, and when Singh's 32-ball cameo was ended by a yorker, with him went Ireland's hopes of getting close.
Just to make sure, Dockrell, Lorcan Tucker and Tyrone Kane all perished in quick succession as the Wolves showed that the failure of the lower-order to score quick runs in a chase was not exclusive to the senior side, although No.11 Peter Chase defiantly hit the seventh six of the innings - matching Bangladesh's tally - before his stumps were uprooted.
Singh was playing his first game for a month since injuring his shoulder at the T20 Interprovincial Festival and was surprisingly not asked to bowl.
He seems certain to get the captain's call tomorrow for the final one-day game, although Harry Tector was also left out yesterday, along with Graham Kennedy and Shane Getkate.
Mizanur Rahman c Chase b McBrine 4
Zakir Hasan lbw b Delany 79
Mominul Haque run out 182
Mohammed Mithun not out 87
Al Amin Jnr c Dockrell b Chase 19
Afif Hossain not out 2
Extras (3lb 10w) 13
Total (4 wkts, 50 overs) 386
Did not bat: Shaif Uddin, Fazle Mahumud, Khaled Ahmed, Shariful Islam, Taskin Ahmed
Fall: 1-6 2-216 3-328 4-361
Bowling: A McBrine 10-0-45-1, T Kane 10-0-88-0, P Chase 10-0-84-1, D Delany 9-0-75-1, S Thompson 3-0-27-0, G Dockrell 8-0-64-0
J Shannon c Rahman b Shariful 2
J McCollum b Fazle 43
A Balbirnie c sub b Khaled 106
S Thompson c Al AMin b Khalded 42
S Singh b Uddin 53
A McBrine c Mithun b Khaled 12
G Dockrell c and b Fazle 10
L Tucker st Mithun b Fazle 0
T Kane c Al Amin b Shariful 6
D Delany not out 7
P Chase b Uddin 8
Extras (1b 4b 6w 1nb) 12
Total (46.1 overs) 301
Fall: 1-19 2-63 3-140 4-233 5-258 6-279 7-279 8-279 9-292
Bowling: Khaled Ahmed 10-0-73-3, Shariful Islam 9-1-53-2, Shaif Uddin 9.1-1-35-2, Fazle Mahmud 10-0-47-3, Taskin Ahmed 5-0-45-0, Afif Hossain 4-0-43-0
Bangladesh A won by 85 runs.