Rory Scannell kicked three penalties and created the only try of the game for Darren Sweetnam as Dolphin handed local rivals Cork Constitution their first defeat of the Ulster Bank League season.
Just past the hour mark, Dolphin out-half Rory Scannell brilliantly unlocked the defence with a neat run and well-weighted pass for fellow Ireland Under-20 international Darren Sweetnam to beat the last defender and touch down on the left.
Scannell's conversion attempt hit the post but despite losing their American international flanker John Quill to the sin-bin, Steve Ford's men hung onto their five-point advantage as Scannell swapped closing penalties with Johnny Holland.
Three Holland penalties were all Cork Con could muster in a local derby that bubbled to life in the second half after a stop-start opening 40 minutes.
The Irish Rugby TV cameras were on site to broadcast the game to a worldwide audience here on the IRFU website, and this Division 1A duel was a gripping contest for those watching.
Dolphin, who lost away to league leaders UCD last Saturday, succeeded in thwarting Cork Con's early advances, with the wind-backed visitors giving away a couple of penalties in advanced positions.
Scannell knocked a drop goal effort wide as Dolphin attached from a Quill-won lineout, and the young number 10 miscued a long range penalty soon after.
The first points of a scrappy, error-strewn opening quarter came in the 12th minute when Dolphin were pinged for not releasing a tackler player and Holland, the league's Young Player of the Year last term, slotted over from outside the 22.
A Cathal Quinn breakaway was called back for an offside decision before a crisp left-footed penalty from Scannell brought Dolphin level at 3-all.
Scannell's radar was off for his third shot at the posts and the turnovers continued up front, with the breakdown area ferociously competitive. There were also a couple of powerful hits from Dolphin captain Christy Condon and Cork Con number 8 Willie Ryan.
Tom Mulcahy's men continued to ship penalties approaching half-time, and referee Nigel Correll lost his patience early in the second half when Cork Con scrum half Ryan Foley was yellow carded for taking out his opposite number Eoin O'Shaughnessy in an offside position.
Dolphin seized the opportunity to go in front with Scannell converting the resulting penalty. 14-man Cork Con were fortunate to survive as home centre John Gleeson was stopped just short of the line following a Cian Bohane run, and winger Harry Fleming was then denied by a foot in touch.
Holland hit back for Cork Con with his second successful penalty as they showed their battling qualities once more, building for a strong finish like the one they produced in defeating Garryowen last time out.
But Sweetnam's unconverted try plus a penalty from Scannell put eight points between the sides with 13 minutes remaining, leaving the visitors with a lot to do.
The sin-binning of Quill invited Cork Con forward and Holland's third successful place-kick set up a grandstand finish with just five points between the side.
Mulcahy's side had chances in the Dolphin 22 but were unable to execute them though – Fleming doing well to prevent Cathal O'Flaherty from scoring – and Dolphin deservedly held on to gain their third victory of the league campaign.
Speaking afterwards, Dolphin head coach Steve Ford told the Irish Examiner: “It was a great performance, it would have been nice to close it out and deny them a bonus point but I suppose I can't complain because this was all about winning.
“It puts us right back into the equation and that was the aim before the game. I’m really happy with the display.”
Referee: Nigel Correll (IRFU)