Dolphin recorded their first AIL double over great rivals Cork Constitution in this hard-fought clash at Temple Hill.
The visitors jumped into an early lead when out-half Barry Keeshan landed a fourth-minute penalty before home skipper Gerry Hurley levelled the match with a penalty.
Following a dust-up between a group of players, Dolphin's Rory Scannell and Con's Ger Sweeney were shown yellow cards.
Keeshan, who kicked a second penalty in the 29th minute, stretched Dolphin's advantage to 9-3 just on half-time.
Dolphin had to face a strong wind after the break, but they defended well and restricted the home side to another Hurley penalty on the hour.
The Cork Con scrum-half had a chance to equalise with a 65th-minute kick at goal, but his shot faded past a post. Dolphin finished strongly to record a famous victory
CORK CON – D Lyons; C Desmond, L Duffy, I Dineen, M Keyes; J Holland, G Hurley; G Duffy, A O'Driscoll, G Sweeney; J McSwinney, C O'Flaherty; G Lawlor, J Ryan, W Ryan.
DOLPHIN – E Mills; D Sweetman, C Bohane, R Scannell, J Gleeson; B Keeshan, C Bannon; D Attridge, W Foley, C Condon; R O'Herlihy, D O'Se; M Cronin, J Quill, R Murphy.
REF – H O'Connell.