Welsh Premier League strugglers Aberystwyth hammered Welsh Cup holders Bala in the third round with a 4-0 win.
There was also a shock as Mid Wales League side Llanrhaeadr beat Cefn Druids 3-2, a team two tiers above them in the domestic pyramid.
Cymru Alliance's Ruthin and Caernarfon Town also claimed scalps.
Ruthin won 3-0 at Prestatyn and Caernarfon beat Barry Town United, who are a level higher in Wales' top fight.
However, Welsh Premier sides Carmarthen, Llandudno, Bangor, Connah's Quay and Cardiff Met progressed.
Lowest ranked side Penydarren BGC have been drawn away at Pontypridd Town in an all south-Wales clash in round four.
Llanrhaeadr-Ym-Mochnant of Spar Mid Wales Division One, winners against Cefn Druids in round three, will welcome another JD Welsh Premier League side to the Recreation Ground in the form of Bangor City.
Caernarfon Town's reward for defeating Barry Town United yesterday is a home tie against The New Saints.
Welsh Cup fourth round draw
(Ties to be played 27-28 January)
Flint v Newtown
Llanrhaeadr v Bangor
Caernarfon v TNS
Connah's Nomads v Porthmadog
Cardiff Met v Aberystwyth
Pontypridd v Penydarren
Llandudno v Ruthin Town
Airbus v Carmarthen