John van 't Schip's side could well be back in South Australia next week to face the Reds in an elimination final. City fans will have to hope that the Dutchman is employing a "rope-a-dope" tactic and trying to lull Adelaide into a false sense of security with such a dismal performance. On the evidence of this display, it's not likely.

The wonder is that it took Adelaide as long as 19 minutes to get their noses in front, so dominant were they from the moment this game kicked off.

It was hardly surprising that they had doubled their advantage within another four minutes, the goals coming courtesy of the Spanish strike force of Miguel Palanca, who put them one up, and Pablo Sanchez, who made it two.

But the best was still to come in the shape of a brilliant Elrich goal in a first half in which everything the Reds tried came off.

That's not to say there was any element of fortune in this comprehensive rout. Far from it.

Van 't Schip's team, which had rescued its season on the back of a gritty five-match unbeaten run through March and early April, simply looked insipid in an opening 35 minutes when the Reds put this game to bed. City had slipped up in Perth last week and wanted to regain their momentum ahead of the finals. What they delivered was a first half-hour that was sluggish, disjointed and lacking conviction.

Adelaide were fluid, direct and played with a pace and verve that City could not match. The fact that they were missing several regulars – Isais, Nigel Boogarde, Marcelo Carrusca, Awer Mabil and Jimmy Jeggo – and were still able to ease to such a commanding lead is an illustration of the way the first half progressed.

City were rather better in the second period, but they could hardly not have been.

The Reds made a lively start when youngster Bruce Kamau made foraging runs down the right and the home team forced numerous corners in the first 10 minutes, one of which nearly brought an opening goal when ex-Melbourne Heart defender Michael Marrone headed over.

City barely got out of their own half and didn't have a shot until the 15-minute mark.

Adelaide got the lead they deserved on 19 minutes through ex-Real Madrid forward Palanca. His countryman  Sanchez did the hard work with a run that took him through the City defence and Palanca finished adroitly.

In the 23rd minute the lead had doubled and once more it was the Iberian connection at play. This time Sergio Cirio made space for himself to shoot. Tando Velaphi did well to beat his drive away, but Sanchez reacted quicker than the City defence and fired home the rebound.

But the best was yet to come  and it was a wonderful goal from an unlikely source in Adelaide defender Tarek Elrich. His good form this season has seen him make his Socceroo debut, but not even he would have expected to score a goal in which he picked up the ball inside his own half, evaded at least four challenges and then finished with the aplomb of a top-level striker.

Adelaide made it four in the second half when Craig Goodwin went down in the penalty area and Cameron Watson, at the second attempt, converted the spot kick, his first A-League goal in 105  games.

Aaron Mooy lent some respectability to the scoreline when he converted a penalty for City in the 65th minute, and the numbers were evened up when Marrone was given his marching orders for a foul on City midfielder Erik Paartalu shortly afterwards.