Lachlan Brook opened the scoring in the 24th minute with a well taken goal and Auckland FC had several good chances to double their lead before halftime.
But Adelaide were always a threat and managed an impressive goal to Harry Crawford, set up by the quicksilver Yaya Dakuly just after the hour mark.
Goalkeeper Michael Woud kept his team in the tie with a stunning early save, while Adelaide Juan Muniz hit the bar in added time.
The home side were cruelly struck by injuries, losing key man Guillermo May just after halftime, before central midfielder Cam Howieson departed a few minutes later.
That was arguably the key period of the match, as Auckland lost momentum and shape, while Adelaide were revived.
The home side also couldn’t keep up the intensity they had displayed in the first half, as the effects of last week’s 120 minute marathon took a toll.
Auckland will take confidence from the performance – especially the first period – as they played some of the best attacking football of their season.
But they will need to go to another level next week, at arguably the most intimidating venue in the A-League.
After their dramatic elimination final win last week, Auckland FC looked on from the start, sharp and hungry. The passing was crisp, the movement confident and they were assertive on the ball.
But Adelaide matched the energy and were dangerous, particularly in transition.
Brook had an early chance – well blocked by a defender – before Woud came to the fore early. He flung himself to his left to push away a curling effort from Jonny Yull, before the save of the night, a quite unbelievable effort to deny Anselmo de Moraes from barely three metres. It was a key moment – as the crowd held their breath – and Woud somehow got in the way of the shot. The goalkeeper was in action again soon afterwards – alert to a long range effort – before Auckland grabbed a foothold.
They pressed and hustled effectively, crosses zinged across and Randall got two shots away. Then came Brook’s moment – against his former club – with an unerring shot into the far corner, after Howieson couldn’t quite connect with a cross and it fell his way. It was fine technique, under pressure, and celebrated wildly in front of the Port. Auckland FC enjoyed their best period from there; Brook seemed untouchable at times as he tip toed down the right sideline, while there was a succession of chances, though Adelaide held firm, helped by some well timed blocks.
The crowd erupted when May scrambled the ball over the line late in the half, before the deflation as it was ruled out for a narrow offside.
Calamity struck the home side early in the second half, as they lost two players in the space of six minutes. First May hurt his calf making a clearance, before Howieson was (accidentally) poked in the eye defending a corner. That meant Jake Girdwood-Reich moved into midfield, with Nando Pijnaker introduced along with Logan Rogerson.
Adelaide took advantage of the reshuffles for their fine equaliser. Dukuly – who was a constant threat – outpaced Sakai to get to the byline – and his inch perfect cross was turned in at the far post by Crawford, who got there just ahead of Callan Elliott.
The game, predictably got tighter, and Auckland couldn’t manufacture the same chances, though Randall and Brook kept prompting.
Francis de Vries made his long awaited return in the 79th minute, brought on with Liam Gillion, who added spark. There were some promising moments – but Adelaide remained resolute, while Gillion connected well to test Vriends.
Muniz was unlucky – with a dipping shot from outside the area that hit the cross bar – which was the final big chance.
Auckland 1 FC (Lachlan Brook 24’)
Adelaide United 1 (Harry Crawford 63’)Halftime 1-0