Cross Keys caused a major shock by securing an unlikely 25-20 triumph at Principality Premierhsip leaders Llanelli.
A penalty try for the visitors was sandwiched between strikes from Owen Jones and Will Johnstone's second-half winner to influct Llanelli's third league defeat of the season.
Llanelli rallied through scores from Mike Davies and number eight Dan Godfrey and the result leaves the hosts one point clear at the top of the Princiaplaity Premiership.
The hosts looked to be cruising with a 17-10 half-time lead at Parc y Scarlets with Dan Evans adding two conversions and a penalty. But Cross Keys went ahead through the penalty try and Johnstone's 52nd minute try.
Evans added a penalty to reduce the lead to 22-20 but opposite number Joe Deakin, who had already hammered home two conversions and a penalty, calmly slotted home a 58th penalty to ease the tension and seal an unexpected win.
Meanwhile. Aberavon cruised to a bonus-point win against Bedwas at the Talbot Athletic Ground.
The Wizards kept their winning run going, after a 74-0 hammering of Division Three club Llantwit Fardre 74-0 in the SWALEC Cup last weekend, and recorded the four tries early in the game.
But they trailed the Premiership strugglers just minutes into the game, but took control early in the second half, scoring tries through flanker Chris Davies and winger Richard Carter within the first ten minutes after the restart.
Bedwas had no response and the kicking of outside-half Jamie Davies saw the game end 38-10 in Aberavon's favour.
Cardiff came from behind to beat Ebbw Vale 15-13 thanks to the contribution of a pair of replacements.
The Blue-Blacks had made nine changes from the XV that lost at Llanelli last week yet it was prop Richard Cornock, who didn't figure at Parc y Scarlets, who came off the bench to help Cardiff secure a win, as late on he pushed over to level the scoreline.
Another replacement, outside-half Gareth Davies, slotted over the conversion to hand the Blue-Blacks four points.
Newport claimed a stunning 34-32 victory over defending champions Neath in a thriller at Rodney Parade.
Tom Riley scored in either half and was ably supported by strikes from Mike Poole and Andrew Coombs in a match which saw the lead change hands nine times.
Neath hit back through tries from Luke Ford and David Lockyer to ensure a losing bonus point for the Welsh All Blacks.
Wales full-back Kevin Morgan started for Newport as the 48-cap star continues his recovery from a serious Achilles tendon injury.
And his influence spread to his fellow backs as early as the second minute when Riley crossed for the opening try.
Newport held a slender 17-16 advantage at the break and were pinned back by the goalkicking of Arwel Thomas who claimed a 22-point tally including six penalties and two conversions.
But Newport replacement kicker Dan Griffiths booted four penalties to get the hosts over the finishing line.
Leigh Bevan was the hero for mid-table Swansea who recorded a comprehensive 39-3 bonus-point victory over struggling Bridgend.
Wing wizard Bevan opened and finished the scoring in a convincing five-try triumph at St Helens.
The hosts were able to include Ospreys' scrum-half Rhodri Wells and his quick distribution allowed his fellow backs to produce free flowing running rugby.
Full-back Nicky Thomas grabbed the second try before adding four conversions and two penalties in an impressive 19-point haul.
Bridgend finally got themselves on the scoreboard when fly-half Gareth David's penalty grabbed their only points on a disappointing afternoon for the visitors.
But Swansea back-rower Sam Kiley added a third for the Whites to put Richard Webster men's into a commanding 22-3 interval lead.
Centre David Watts grabbed the bonus-point for the home side early in the second period before Bevan sealed victory with his second score.
There was a tie on Saturday at Glamorgan Wanderers and Pontypridd both scored 13.
Scott Sneddon scored a penalty with the last kick of the game to seal a stunning second-half comeback from the Wanderers.
The result leaves both sides safe in mid-table with little prospect of any end-of-season nerves at either end of the table.
Pontypool emerged narrow 10-6 victors over Llandovery in the Welsh Premiership basement battle.
Tries in either half from Sam Mills and Gareth Williams handed the bottom side only their fourth win of the season at Church Bank and leave them five points adrift of their nearest rivals.
The Half a Game initiative is currently sweeping across Wales and proving a major success. The scheme aims to give every young player at least half a game every weekend. WRU TV recently visited a festival in Narberth where clubs have fully embraced the initiative.
Both Bargoed and Swansea were seeking their first win of the Principality Premiership season this afternoon. It proved a fruitful day for the hosts - not only did they win, but Bargoed claimed a try bonus point.
Cardiff managed to keep their unbeaten record at home intact, but only just as Bridgend made them work extremely hard before the Blue and Blacks secured a hard fought Principality Premiership win at the BT Sport Arms Park last night.
Former Wales back row Andy Powell gives a guided tour of The Wern, home of Merthyr RFC, who are determined to prove a lot of people wrong and make their mark in their first season in the Principality Premiership.
Wales Sevens head coach Gareth Williams looks back on the Rio Sevens success where he helped GB win silver. He believes the successful campaign is a huge boost to his Welsh squad as they prepare for another World Series, as WRU TV's Graeme Gillespie discovers
British and Irish Lions head coach Warren Gatland will be heading back home to take on the All Blacks next year where for him, success for 2017 is all about going to New Zealand and winning a Test Series.
Last week all roads led to Eugene Cross Park where defending champions Ebbw Vale hosted this season's launch of the Principality Premiership. WRU TV's Graeme Gillespie was there to capture the thoughts of Damien Hudd, captain of Ebbw Vale, and WRU Head of Performance, Geraint John.
Llandovery made it three in a row when they defeated Aberavon in the final of the National Foster's 7s at BT Sport Cardiff Arms Park on Sunday. On another eventful day of sevens, Newport claimed the Plate and the Dragons won the women's crown
Last week saw Cardiff welcome players from around the world for the 21st Golden Oldies Festival. The tournament features players over 35 years of age, and this year's event saw a select few represent the WRU in a 'friendly' against the Wooden Spoon.
Wales Under 18 captain Callum Bradbury is delighted to have seen his side claim a narrow 18-17 victory against a strong SA Schools 'A' side to end the three-match Under 19 International Series in South Africa on a high note.
The Wales U18 squad spent an emotional day in the drug-riddled townnship of Hout Bay. Hout Bay Warriors President Fred Johannes said the visit was 'the talk of the town' and will dream about the day everyday for the rest of his life.
RGC 1404's new head coach Mark Jones is hoping to build 'something special' in north Wales and is already looking forward to the development region participating in the Principality Premiership for the very first time.