Analysis: Reds will be confident facing Wanderers

Adelaide United coach Guillermo Amor would have enjoyed Western Sydney Wanderers' pulsating 5-4 triumph over Brisbane Roar more than most, with the defending questionable at best.

As entertaining as the Wanderers' incredible comeback was, the defensive errors from both teams only served to underline the disparity down back between Adelaide and the rest of the A-League this season.

The semi-final at Pirtek Stadium should give Amor and Adelaide fans plenty of confidence that the Reds can claim their first Championship next week when they host Western Sydney at the Adelaide Oval.

After conceding 17 goals during their eight-game win-less run to begin the 2015-16 campaign, Adelaide finished the regular season having let in just 28 - the best defensive record in the competition.

Dylan McGowan celebrates Victory with Reds teammates Eugene Galekovic and Jordan Elsey.

Amor's defensive structure was a critical part of Adelaide lifting the Premiers Plate and - after Sunday's semi-final - those tactics look likely to lead the Reds to their maiden A-League championship too.

In their last 10 matches, Adelaide have conceded just six goals and kept six clean sheets.

By comparison, the Wanderers have conceded 17 goals in the same period, keeping their opponents scoreless twice, while Roar let in 23 and notched two clean sheets.

All eight goals in regulation time were eminently avoidable at Wanderland. 

A silly handball in the 15th minute from Wanderers midfielder Andreu allowed Dimi Petratos to give Brisbane the lead against the run of play via a penalty.

Andreu doubled the visitors' advantage soon after with an own goal off his rear end, after Alberto shoved Jamie Maclaren in the back to concede a free-kick in a dangerous area.

It was a poor start for Western Sydney's Spanish contingent and it continued in the 23rd minute as Alberto allowed Jamie Maclaren to get in front of him to receive Brandon Borrello's cutback, and Brisbane's leading goal-scorer converted on the turn.

The Wanderers' comeback started just three minutes later thanks to Romeo Castelen's thunderous free-kick, although Roar coach John Aloisi would surely have been unimpressed by Brisbane's wall or the positioning of goalkeeper Jamie Young.

Western Sydney striker Brendon Santalab would be the next to score, bursting away after Brisbane's defence were caught square by a long-ball over the top, as the home side went into the break just 3-2 down.

The Wanderers would hit the front by the hour mark thanks to two more goals from Castelen, and on both occasions Brisbane failed to effectively clear the ball from a set-piece situation.

Then in the 81st minute, three Western Sydney defenders were dragged out of position by Henrique, leaving Maclaren unmarked in the penalty area to tap in his 20th goal of the season.

To be fair, the Wanderers deserved to win as they finished the match with 12 shots on target to Roar's four.

Young made some incredible saves for Brisbane throughout the contest but still arguably could have done better for the decisive goal from Dario Vidosic.

The 30-year-old goalkeeper parried Vidosic's initial strike in play rather than around the post in the 13th minute of extra-time, which allowed Mark Bridge to regather possession and square a cross for his team-mate's tap-in.

This was the A-League at its ridiculous best but when Western Sydney coach Tony Popovic reviews the game this week, he won't be impressed by how his team defended.

Amor, on the other hand, should have plenty of faith his well-balanced and well-drilled unit can see off the Wanderers' challenge in the grand final.

Adelaide United will face Western Sydney Wanderers in the 2016 Hyundai A-League Grand Final on Sunday, 1 May at Adelaide Oval. Kick-off is at 3.30pm ACST.