In the upset of the day, defending champions Llanelli have been knocked out by fellow Premiership side Llandovery, with former Stradey Park player Tomos Marks kicking seven goals in a thrilling 29-21 victory.
Welsh Districts side Bryncethin Sports - the lowest-ranked team left in the Cup - looked like causing an upset of their own when they took an 8-0 lead over Division 1 side Caerphilly, but tired in the second half to lose 22-8.
Premiership side Aberavon were too good for Division 1 strugglers Fleur De Lys, with prolific points-scorer Jamie Davies crossing for two tries and kicking nine conversions in the 68-15 victory. It could have been worse for the visitors if Fleur captain Richard Jones and scrum-half Daryl Cooke hadn't bagged late tries.
Bridgend fullback Gareth David scored two of the Ravens' seven tries against a brave Cwmllynfell outfit at the Brewery Field, while Swansea were made to work hard before leaving Corus with a 24-10 victory. The win came at a cost, though, with talented All Whites outside-half Luke Richards taken to hospital with an ankle injury.
Division 2 East side Rhydyfelin upset Division 1 outfit Blackwood 17-15, with winger Nicky Nicholas silencing the home fans with a last-minute try to steal the victory. Maesteg ran in eight tries in a comfortable 62-10 win over Kenfig Hill, while Narberth scored seven in a 46-0 shutout of Barry.
Results: Aberavon 68 Fleur de Lys 15, Abercynon 29 Machen 19, Blackwood 15 Rhydyfelin 17, Bridgend 47 Cwmllynfell 10, Bryncethin Sports 8 Caerphilly 22, Brynithel 6 Pencoed 27, Carmarthen Quins 28 Pontypool 14, Corus 10 Swansea 24, Heol y Cyw 10 Ebbw Vale 37, Llandovery 29 Llanelli 21, Laugharne 12 Cardiff 39, Maesteg 62 Kenfig Hill 10, Merthyr 38 Cilfynydd 13, Nant Conwy 24 Tylorstown 6, Narberth 46 Barry 0, Newport 21 Beddau 3, Penclawdd 32 Glyncorrwg 5, Pontyberem 0 Pontypridd 20, Pontypool United 10 Llanharan 12, Taffs Well 3 Neath 86, Taibach 5 Dunvant 44, Tonmawr 27 Mountain Ash 15, Tonna 30 Pill Harriers 10, Trebanos 15 Builth Wells 40.
Postponed: Cardiff HSOB v Kidwelly, Cross Keys v Bedwas, Glamorgan Wanderers v Ystrad Rhondda, Mumbles v Llangennech, New Tredegar v Newport Saracens, Penallta v Bonymaen, UWIC v Llantwit Fardre, Whitland v Bridgend Athletic