Adelaide United claimed a second win in a row over Melbourne Victory on Friday as George Blackwood secured a 1-0 victory on Friday.
The 21-year-old's header in the 81st minute settled a scrappy Original Rivalry clash at Coopers Stadium that boosts their chances of hosting rights for their first match in the finals series.
Chances were scarce in something of a nervy first half, although Ola Toivonen and Nikola Mileusnic each came close to breaking the deadlock just before the break.
Georg Niedermeier sent a header narrowly wide, but Blackwood made no mistake with what proved to be the only effort on target of the match, meeting Isaias' cross from the right and powering the ball beyond goalkeeper Matthew Acton.