Down booked their place in the semi finals of the Irish Challenge Trophy thanks to a "golden goal" winner in extra time from Richard Owens.
The goal marked the end of what was a seven-goal thriller against the side from north Dublin which included two former Irish internationals in its line-up, brothers Mark and Matthew McCann.
In a classic cup tie, Down looked dead and buried with just minutes to go as they trailed 3-2, but Owens popped up with the equaliser and then scored that dramatic winner in the first minute of extra time.
Owens, who started the game in defence alongside skipper, Jeremy McCready, was moved into his customary middle of the park role in the second half and transformed the game. Suddenly, Portrane were forced on to the back foot as they struggled to cope with Owens' probing runs.
Down started well against a side which has played a lot of its hockey on shale over the years and the Malone Park pitch held no fear for them. In fact, they revelled in the conditions with their stopping and passing particularly impressive.
The home side was keen to make an early impression and while Paul Tate and Mark Elliott combined early only, Portane's veteran 'keeper, Macdara Delargey kept them at bay. In fact the 54 year-old, yes, the 54 year-old, produced a number of top saves and on more than once occasion, frustrated the home forwards.
Adam McKee fired wide in the fourth minute while Stephen Ferguson sent Tate racing through but he was denied by the 'keeper. At the other end, Owens produced a great tackle to rob Matthew McCann and then Sinclair White saw an eighth minute short corner blocked by Delargey. The 'keeper, who was in inspired form, then denied Owens from a short corer in the 10th minute.
Chris Lennon vacated his full back berth to go on a surging run in the 13th minute, picking out White who was again denied by Delargey. The deadlock was broken one minute later. Tate's powerful run into the penalty area resulted in his shot being saved, but Elliott spun on a sixpence to crash the ball home.
Peter Conway, who was rock solid at the heart of the Portrane defence, was outstanding and also fizzed to short corner shots past Mark Johnston's posts in the 20th and 21st minutes. He was then denied by a great tackle from James Erskine just as he was about to pull the trigger.
Matthew McCann then saw a shot flash past the post as the visitors signalled they would be no easy pushovers.
Johnston produced a smart save to deny Conway in the 24th minute, but he was powerless to stop the visitors getting back on level terms two minutes later and what a peach of a goal it was. Conway drove the ball into the heart of the Down penalty area where Matthew McCann used all his experience to deflect it into the net.
Back came Down and Paul Neill's great run ended with a cross to Taylor whose rasping shot was deflected over the bar. At the opposite end, Johnston produced a brilliant diving stick save to deny Conway from a short corner.
Neill then almost put his side ahead after great work by Taylor, but he couldn't get his body turned to drag the ball home when unmarked at the back post. With just seconds of the half remaining, Gavin Ringland picked out Tate, but his goal-bound shot was deflected over the bar.
It was anyone's game and within eight minutes of the restart, Portrane went 2-1 ahead after being awarded a penalty stroke when Johnston upended Matthew McCann.
Former Leinster inter-pro star, Peter Byrne, stepped forward to score, but Johnston got a stick to the ball and almost kept it out. Delargey again denied White from a short corner while Owens was left with his head in his hands after Byrne cleared his goal-bound shot off the line.
Johnston kept his side in the game with another super save to deny Conway before Taylor rushed his shot when he had more time than he thought to pick his spot past Delargey. The visitors' 'keeper then denied White again before somehow blocking a Ferguson blockbuster.
Tate scored the all-important equaliser in the 68th minute following a great run by Owens who was far more influential in the middle of the park. Down were delighted to be back on level terms but Anthony Carroll scored to make it 3-2 with just minutes to go.
The home side wasn't going to go out without a fight and that man Owens scored from a short corner with two minutes to go to send the tie into extra time.
A golden goal would win it for either side now and it was fitting that Owens, who transformed his side's fortunes in the second half, should be the man who scored the winner with a clinical strike from a short corner, awarded after a brilliant run by Taylor ended with him being fouled.
In the semi-finals, Down will be joined by derby rivals Saintfield, Mullingar and Campbellians. The draw will be made within the next few days.