Birkenhead United have won the Chatham Cup for the first time - but only after watching it almost escape their clutches.

Leading 2-0 over Waitakere City with five minutes to play on Sunday, they conceded twice, first to Dylan Manickum, who had been threatening all afternoon, and then to Keegan Linderboom from the penalty spot, a goal that sent the game to extra time.

There, the club from Auckland's North Shore had to respond to having a man sent off - defender Ryan Cain - and it was only after a couple of chances went begging for Waitakere that they found a winner, when Ethan Galbraith scored with 10 minutes remaining.

PHOTOSPORT Waitakere's Jake Butler controls the ball under pressure from Birkenhead's Sam Burfoot.

Waitakere keeper Ross Nicholson appeared to have collected a cross cleanly, but then lost control of the ball, and so Galbraith fired home, amidst howls of protest that there had been a foul in the process.

READ MORE: Chatham Cup final a long time coming for Birkenhead

The result was sweet relief to Birkenhead's Red and White Army, who combined with Waitakere's smaller, but no less vocal contingent, to produce an atmosphere at Albany's QBE Stadium that was fitting for the occasion.

Birkenhead defender Tom Davis, who won the Jack Batty Trophy as the most valuable player in the final, said the fervent crowd was standard for them.

"The community support that we get at Birkenhead is amazing, and we wouldn't be the club that we are without these people.

"Week-in, week-out they come and I'm not surprised that everyone's here - it's just amazing."

They were witnesses to a heated contest, with three players going in the book inside the first four minutes, and several others joining them there as the game unfolded. The dismissal of Cain in the first period of extra time, after he went shoulder to shoulder with Manickum and received a second yellow card, was an inevitable occurrence in the context.

Former All White Jarrod Smith gave Birkenhead the lead in the 23rd minute, shooting past Nicholson from the right-hand side of the box, and finding the far corner of the net, and then added a second in the 38th minute, shooting from right in front of goal after the Waitakere defence allowed Godwin Darkwa and Dan Morgan to lay the ball on a plate for him.

Waitakere's best chance of the half came in the minutes right before halftime, when Manickum was able to round Birkenhead's keeper, Damian Hirst, but had his shot cleared by Christian Gray a metre from the line.

Both sides produced chances at the start of the second half, but couldn't find the back of the net, Waitakere's best coming when Steven MacDonald was played in behind near the hour mark, forcing Hirst to make a double save, and Birkenhead's shortly before that, when they couldn't get a clean shot off in a goalmouth scramble.

Needing at least two goals as the game entered the final half hour of regulation time, Waitakere began to hold more and more of the ball, but couldn't break through.

Birkenhead should have added a third and put the game to bed with 10 minutes to go, only for Morgan's shot to hit the left post - a miss that in the end didn't matter, but almost proved costly.

Having worked tirelessly all game, Manickum finally got his name on the scoresheet, poking the ball past Hirst in the 86th minute, a goal that gave his team hope, which they immediately seized on in winning a penalty that Linderboom converted to level the scores up 2-2. The Birkenhead player at fault appeared to have been Gray, who might have clipped MacDonald's heels when the lanky forward entered the box in the 89th minute, but it was far from a clear-cut decision.

Extra time began cagily, Birkenhead looking to compose themselves, and Waitakere not wanting to give up the lifeline they had just grabbed, and five minutes in, the game took another twist, when Cain was sent off.

​Both sides had chances in extra time, but it was Galbraith who made his count, and having already got out of jail once, Waitakere couldn't a second time, although Manickum did give it a try, shooting across goal from a narrow angle in the dying seconds.

AT A GLANCE

Birkenhead United 3 (Smith 2, Galbraith) beat Waitakere City 2 (Manickum, Linderboom pen) after extra time

HT: 2-0