McGowan nailed a free header in the 87th minute to settle a feisty Friday night encounter at Adelaide's Coopers Stadium.

After Sydney's Adam Le Fondre produced a rapid first-half brace, Adelaide rallied with replies to Nikola Mileusnic and Al Hassan Toure.

And just as the fizz appeared to be dwindling, South Australian-born McGowan produced the decisive moment of his first A-League game.

Unmarked from a Brandon O'Neill corner, McGowan floated to five metres from goal and sweetly hammered a header.

"It's nice to come here and get a win," said Sydney coach Steve Corica.

"I'm pleased with the win and the performance - it can get better but it's the first game."

The season opener also included a straight red card to Adelaide's Ryan Strain, who was marched for felling Le Fondre in a second-half sprint towards goal.

And the fresh campaign featured three video assistant review flashpoints, including an offside call which denied a goal to new Sky Blue Kosta Barbarouses.

The VAR system also decided Adelaide's lively newcomer Toure had squared scores 2-2.

In a narrow call, Toure was ruled onside when teammate Riley McGree played an audacious lifted pass which paved the path to goal.

Toure's score lifted the 9,903-strong Adelaide crowd which had earlier slumped after Le Fondre's quick-fire double.

Just 20 minutes in, referee Alex King halted play for a VAR check - he watched replays of a Le Fondre clip brush an arm of Adelaide captain Michael Jakobsen inside the area, and awarded a penalty.

Le Fondre duly scored, thumping into the top right netting.

Some six minutes later, the Englishman started and finished a flowing play which diced Adelaide's defence.

Le Fondre supplied Milos Ninkovic, who played Alex Baumjohann into space and the German's cut-back across the goal-face precisely found Le Fondre for a tap-in.

But Adelaide answered just before halftime when Sydney's Baumjohann tangled with Ryan Kitto and the Reds were given a free kick some 20 metres out.

Mileusnic produced a stunner: a curling strike which eluded a diving Thomas Heward-Belle.

"The whole game we were a little bit unlucky ... I saw a team who played very good football, a lot of chances," said Adelaide coach Gertjan Verbeek.

Australian Associated Press