"The game was there for us, but we couldn't finish it off," Waunarlwydd coach Jason Hyatt said. "We scored two early tries but then took our eye off the ball. We were right in at 17-all with 10 minutes left, but they scored off a charge-down and you can't do much about that sort of thing."
Elsewhere, runaway leaders Bonymaen suffered a shock home 29-all draw to struggling Blackwood. Unbeaten Bonymaen led an entertaining match 29-22 at halftime, but couldn't add to their score as 14th-placed Blackwood hit back to earn a draw. The result gave second-placed Newbridge a chance to narrow the gap at the top, but they made hard work of it with an 18-14 home win over Llangennech. Visiting winger Matthew Jacobs scored a try in each half, but second-half efforts from flanker Martin Ackerman and scrum-half Matthew Taylor edged Newbridge in front.
Whitland cemented their top-four position with a 25-17 victory at bottom-placed Fleur De Lys, with Whitland winger Will Davies and Fleur scrum-half Darryl Cook both bagging a brace of tries.
Merthyr fly-half Neil Burnett scored a try and kicked 15 points in his club's 30-11 win at Llanharan. The home side trailed only 9-8 at halftime, but Merthyr moved up a couple of gears in the second spell of a match marred by four yellow cards.
Caerphilly backrower Geraint Leyshon scored two tries in the Castletown men's 21-8 win at Narberth, while winger Peter Thomas kicked 16 points in Cwmllynfell's 36-18 win over Builth Wells.
Second-from-bottom Ystrad Rhondda couldn't come up with a starting XV for their match at Beddau, and were forced to ask for a postponement.