They shot out to an early 2-0 lead against higher-ranked opponents in City Development but, despite no lack of endeavour, were unable to hold out and succumbed 3-2 at the final whistle.
It is a result which sees Celtic end their season - though they have the consolation of being Wanganui league champions.
Another side to bow out were the City Braves, as Athletic Cosmos continue their great run of results late in the season. A convincing 6-2 victory for Cosmos sees them into the last four.
The cup standings have Wanganui City with 15 points; Wanganui Athletic 12pts; City Development 6pts (third on goal differential) and Athletic Cosmos fourth also with 6pts.
In the plate competition it was goodbye for the season to the City Thirstys.
They took an early lead against their clubmates, the young City Rockets, but could not maintain the effort and were beaten 3-1, having had a goal disallowed.
Castlecliff United continued a winning momentum with a 3-1 win over the Marist Casuals to seal their own plate semifinal spot next Saturday.
Casuals miss out on the semis. They will be wondering if the length of the season started to takes its toll physically.
City Hammers reinforced their favourites tag in the plate with a convincing first-half performance which saw them overcome a tidy Athletic Weekenders 7-1.
The Weekenders took the lead early on and looked dangerous before the unbeaten Hammers fired into action with some neat passing which produced the goals.
The Hammers finished top in pool play but not even goal difference could separate Castlecliff and City Rockets who ended up equal second with 9 points, 12 goals for and 12 goals against.
The Weekenders pick up that fourth spot with 6 points.
In the crunch game between the two title contenders in the women's league, Collegiate secured the championship with a 2-0 win over Athletic Women.