Both teams jockeyed for an advantage in the first half on a bright sun-soaked afternoon. The large crowd found that their attention was held in the attritional contest, where the Otters had the bulk of the ball, but found their path to the line blocked repeatedly by the stalwart defending of the Borderers.
Although the sun was shining, most spectators - and some players - wore gloves on their hands as it was extremely cold.
The first half was littered with handling errors as the players kept trying to move the ball up field. Supporters thought that the temperature was a bit of a problem, but the players said after the match that it was the sun which caused the errors, as they had difficulty in sighting the ball when it was moved across field.
Whitland fly-half Carwyn Jones gave his team an early lead after 10 minutes with a penalty from just outside the 22, but he was off target with a drop-goal attempt after 33 minutes.
The only try of the half came when Narberth winger Nick Jones went over for an unconverted score in the left corner after 40 minutes.
Otters' outside-half Aled Davies had seen his penalty attempt hit the left upright, but minutes later when Narberth were still in an attacking position, Jones had just enough space from an overlap to race over to give his team the lead.
It was short-lived, though, as two minutes later, the Borderers regained the lead when Carwyn Jones was on target with a short range penalty kick.
Narberth did have one more scoring chance in the eighth minute of injury time, but Aled Davies saw his penalty attempt sail to the left of the posts
Aled Davies had more success with his next penalty kick to nudge Narberth in front when he slotted over a penalty after seven minutes of the second half.
Gradually the continuing attacking moves by the Otters paid dividends. Winger Tom Bonnell scored in the right corner after 11 minutes when full-back Matthew Davies came up into the line and judged the timing of his pass to perfection, to enable Bonnell to show his pace for the visitors to increase their lead with an unconverted try.
Eight minutes later, the Narberth lead was extended with a well-judged drop-gaol by Aled Davies.
Number eight Jamie Bohata charged down an attempted clearance kick by the Borderers and showed his footballing skills to kick the ball ahead. Replacement wing Jonathan Morgan followed up and slipped the ball to centre Steve Martin, who grabbed the half chance to score a try, converted by Aled Davies.
The try-scoring was completed when, after 38 minutes, Narberth flanker Andrew Dennis capped a fine display by darting over from a Whitland lineout in the right corner, and this was converted by Aled Davies.
Speaking after the match, Narberth director of rugby, Jonathan Dodd, said: "We are very pleased with the win and to get a bonus point. Very rarely do you get a big score in these local derbies.
"In some respects, it was a poor first half for both teams, but in the second half we strung a few phases together, passes started to stick and we scored some nice tries.
"The coaches were pleased with our performance today and the way in which we continued to play rugby.
"It was a good occasion. It was nice to have a derby game on a Christmas Bank Holiday like the old days.
"Before the interval, players of both teams had difficulty in seeing the ball during cross-field passing movements because of the angle of the sun and the ball was also slippery.
"We played in the right territory and we had a bit of tempo to our game. The bonus point win has moved us up to third spot in the league table.
"There were good performances by flanker Andrew Denis, centres Steve Martin and Richard Davies, winger Tom Bonnell, lock Alex Jenkins, number eight Jamie Bohata and flanker Gareth Bateman, who was the team management's choice as the Narberth man-of-the-match."
Whitland spokesman Richard Merriman gave an objective assessment when he reflected on the game and conceded that Narberth deserved to win.
He said: "We were beaten by the better side. Our defence in the first half was excellent and made sure that we were in front with a six-five lead at half-time, although we might not have deserved to be leading at the time.
"In the second half, Narberth stepped up a gear and Steve Martin had a superb game. Narberth outside-half Aled Davies kicked well out of hand and did not throw any loose passes."
Whitland were missing a number of key players through injury, but the Whitland spokesman did not dwell on this fact as it is a problem which all teams, at whatever level, face from time to time.
He added: "We competed fairly well. Flanker Jack Mason had a very good game against his former club, skipper Randall Williams was immense, despite playing out of position in the second row, centre Lee Glanville had a good all-round game, but we do not have quite enough strength in depth at the present time.
"There is no argument about it. The match was played competitively in excellent spirit and on the day Narberth deserved to win."
On Saturday, January 3, Whitland will be home to bottom-of-the-table Dunvant and Narberth will have their first league fixture at Felinfoel. The teams have met previously at Felinfoel in a cup fixture, but it is the first league encounter between the two clubs.
Match sponsors Mason Bros, of Lampeter Velfrey, Young Bros, of Llandissilio, Taylor Tiles, Neil Jolly, Allen and Partners and Folly Farm, of Begelly, nominated Whitland captain Randall Williams as the man-of-the-match.
Tam sponsors were Vicky and John Gardner and the match ball sponsors were Phil Williams, Ieuan Griffiths, Mark Wade and Gwen Davies, Graham Searle, K. P. Thomas and Sons, Haverfordwest Coins, Arthur Lewis, Mary Pearce, Ben Freeman and Friends, Wilde Sports and A. N. Morgans, of Whitland.
Narberth fielded: Mathew Davies, Tom Bonnell, Steve Martin, Richard Davies, Nick Jones (Jonathan Morgan), Aled Davies, Adrian Killa Andrew Davies, Ryan Perrott (Tom Slater), Dan Smith, Justin Hughes (capt.), Chris James (David Ebsworth), Alex Jenkins, Gareth Bateman (Richard Sharpe-Williams), Andrew Dennis, and Jamie Bohata.
Whitland fielded: Will Davies, Gareth Morris, Aled Jones, Lee Glanville, Dan Mason (Gary Evans), Carwyn Jones, Gareth Davies, Gareth Lloyd (Gareth Williams) Alan Proctor (Gavin Walsh), Richard Smith (Rhun Morgan) Randall Williams (capt.), Carwyn Davies, Gareth Davies (Ryan Michael), John Bowen and Jack Mason.