The Cymru South's hopes of reaching the UEFA Regions Cup finals are over after a 3-2 defeat to the FA of Vojvodina.
Llantwit Major goalkeeper Jack Lansdown was sent off as Andy Hill's side capitulated again in their second group game in Serbia on Monday.
Back-to-back defeats mean the Welsh representatives will not be able to qualify for the finals in Milan, due to be held at the end of the season.
De Cymru went ahead through an early penalty from Pontypridd United's Liam Eason after eight minutes, before Alex Bonthron (Cwmbran Celtic) doubled their lead with his second goal of the tournament on 62 minutes.
But just three minutes later, an own goal for Josh Allen provided the catalyst for the Serbians to stage a late comeback.
Bratislav Jelic equalised in the 85th minute before Lansdown was shown a straight red card - and his replacement Dion Carroll was beaten by a 96th minute winner from Dejan Mitrovic.
Lansdown's Llantwit teammate, winger Matty Kimmins, was left on the subs bench as the Cymru South's hopes of European silverware came to an end.
De Cymru's final game of this year's tournament sees them face North Macedonia on Thursday afternoon.

Why Llantwit Major's roads lead to Rome...
Barry scrape past Rhiwbina in youth league
Rangers sign keeper Kelly on loan
Barry fall to Welsh Cup upset
Barry's Welsh Cup run reaches Sunny Rhyl
Evans equalises on Llantwit return
Dinas build momentum with Fairwater win
Penarth out of Division One Cup
Swans hit Barry Ladies for seven
Bombers stun Llanishen with late show
Kenyan safari for Barry bowlers
Barry rout Brynmawr in youth friendly
Barry beaten in phase two opener
Llantwit rained off again
Llantwit sign keeper Gardiner
Wharton returns to Barry Town
Grady recalled for Six Nations