Ex-Cardiff Blues fly-half McCarthy bagged a staggering 28 points including two tries and a last-minute penalty to snatch a famous win at the Memorial Ground while the All Whites stole an early march on rivals Cardiff with a 36-30 triumph at the Arms Park.
Neath and Pontypridd meet at the Gnoll in a repeat of last season's Konica Minolta Cup Final with both sides desperate to rediscover their cup form after losing their opening games of the new campaign.
Wales defence coach Rowland Philips will demand nothing less than victory on home soil after that defeat to Glamorgan Wanderers as they chase a hat-trick of Premiership titles. Pontypridd also stumbled at the first hurdle, falling 33-13 to Llandovery at Sardis Road last weekend, and will be anxious to register their first points of the season.
Last season's runners-up Bridgend slipped up 16-7 at Ebbw Vale last week but will be aiming to get back to winning ways at home to Cross Keys who lost the first Gwent derby of the season against Bedwas.
Cardiff play host to Llanelli at the Arms Park with the visitors looking to continue their winning start following their nail-biting 17-16 win over Maesteg, who take on visiting Bedwas.
Aberavon travel to Llandovery in search of three points and buoyed by last weekend's first ever league win at Newport who face Gwent rivals Ebbw Vale.
The Wizards, with 14 points from the boot of outside half Jamie Davies, inflicted a 19-6 defeat on the Black and Ambers for their first win at Rodney Parade for 22 years and will be hoping for the same again.