Lansdowne got the win they required to keep the heat on table toppers Terenure, but they did not have it all their own way against Dolphin at Irish Independent Park.
Mike Ruddock's men were 37-6 winners over Dolphin in September's opening round and would have been hoping to push for another bonus point against the division's bottom side.
Nonetheless, a number of British & Irish Cup call-ups left them short of some key backs and they had to hang tough to record a 13-6 triumph in the end, with their captain Ron Boucher forced off through injury.
Two Barry Keeshan penalties had Dolphin leading 6-3 at the turnaround, with John Quill and Eamonn Mills both impressing in what turned out to be a real dogfight.
But the visitors levelled through Scott Deasy in the 48th minute and a penalty try in the closing stages, which the home crowd felt was dubious, proved to be the match winner for Lansdowne.
In fact, the headquarters club, who dominated both possession and territory, had their patience tested as their try did not come until the 71st minute when their superior scrum earned them the day's decisive score.
Credit must go to Dolphin who tackled their hearts out and put in another wholehearted performance on home turf, with lock Dave O'Mahony and the Quills typifying the collective effort up front.
Both sides were missing players due to injuries and B&I Cup games, and Dolphin head coach Steve Ford is eager to have his full complement available again as they look to close the gap between themselves and the sides above them.
“In this division you've got to be good without the ball and that was an area we have really tried to work on. It came down to a scrum at the end of it, although I admit Lansdowne had an awful lot of territory and we were under pressure throughout,” Ford told the Irish Examiner.
“Sometimes the games are like that and you've got to fight and a lot of those boys grew up out there. We were missing some of the (Munster) 'A' boys and we still have injury concerns.
“Hopefully some of those lads will make their way back in the coming weeks. We're at the halfway point now (sitting six points adrift at the bottom) and we've got to start getting the points together.”
Giving his assessment of the game, Lansdowne boss Mike Ruddock said: “We had lots of new combinations so we lacked cohesion and gave away a lot of penalties. There's a lot of talk these days about winning ugly and sometimes you've just got to win ugly away from home.
“We knew Dolphin would be dangerous, they're bottom of the league but they are better than that. We knew they would scrap for their lives and they certainly did that.
“Anyone who predicted we would come down here and put 20 or 30 points on them would have to be mad, especially with the injuries we have, with the B&I Cup taking some of our players and, of course, because of my firm view Dolphin are better than their position.”
Referee: Mark Connolly (IRFU)