Dunvant were denied their first win of the season by a controversial injury-time try for Felinfoel.
The basement Division One West side had lost their previous 21 league matches this season. But they looked certain to break their duck before Luke Marsh touched down to secure a narrow 31-27 victory.
It was scrum-half Marsh's second score of the afternoon but the hosts claimed the ball had not reached the try-line.
Sam Crowley, Mike Arnold and Lee Tucker crossed for Dunvant but Felinfoel had already scored tries through centre Ryan Nicholls, fly-half Stuart Wall and former Dunvant player Simon Delaney.
Second-placed Tonmawr gained a bonus-point 33-10 away win at third-placed Narberth with wing Ryan Davies grabbing a double to assist Hywel Davies, Steve Lewis and Mickey Evans.
Cwmllynfell beat Carmarthen Athletic 34-22 and Whitland and Bonymaen shared the spoils in a 15-15 draw. Carwyn Jones scored all the points for the hosts with tries from Robbie Ford and Duane Eager.
Division One East Champions Blackwood hammered Caerphilly 86-24 thanks to hat-tricks from the James brothers. Both Trevor and David James crossed three times each in an 11-try blitz against the fifth-placed outfit.
Luke Knight added two tries while Mark Birkley and Adam Coupe completing the scoring while the home side scored consolation touch downs through James Walby, Keiran Phillips and fly-half Dan Ellis who claimed 14 points.
It was a try-scoring feast across the three games played in the division with UWIC running in eight tries in their 49-15 romp over Merthyr.
Bargoed moved into fourth place in the table with a convincing 29-15 victory over Rumney. The hosts raced into a 24-5 interval lead with wing Gary Jones grabbing a double along with Rhys Humphreys, Lewis Wayman and Danny Jones.
WRU TV were on hand at the launch of a major new commercial deal with WRU and Mercedes-Benz South Wales (part of the Sinclair Group), which sees the family company become an official supplier to the Welsh Rugby Union
On the back of the recent Women's Rugby World Cup, the WRU has launched a revitalised Women's and Girls domestic seasonal structure, and the future is looking bright.
Go to www.wru.co.uk/tryourgame for more information
Roger Lewis talks to WRU TV at the announcement of a new £60 million Rugby Services Agreement (RSA) which provides a new and positive contractual relationship between the WRU and its four Regions for the next six years has been agreed.
The Welsh Rugby Union has announced a major new sponsorship deal with Gullivers Sports Travel which will make the UK's leading, and longest established, multi-sport tour operator, an Official Supplier for the rest of the decade.
Having taken part in seven World Cups as a player and coach, Liza Burgess hopes to go out in style this afternoon when Wales take on Australia in the Play-off for seventh and eighth place in the Women's Rugby World Cup in Paris.