The victory halted United’s six-game unbeaten run and moved Roar to within a point of the league leaders.

An industrious performance nullified United’s attacking threats and when it was needed Reinaldo provided the quality with a tremendous 63rd minute goal that deserved to win any game.

Capitalising on a headed knock-down from Robbie Kruse, the big striker smashed the ball into the top corner past the helpless Eugene Galekovic in the Adelaide goal to send the Roar bench into raptures.

It was just reward for Reinaldo whose toil in recent weeks has brought praise from coach Frank Farina and the goal will be a massive confidence booster for the Brazilian.

But it's back to the drawing board for Reds' coach Aurelio Vidmar.

“It just wasn’t our night," he said.

"We looked flat right from the start and couldn’t get into the groove so I think it was just generally everyone felt pretty much the same.

"We didn’t have any run in our legs and that’s the result.”

He added: “Obviously I’m not happy that we lost, we spoke at half time that there would probably only be a goal in it and as it turned out it was.

“We weren’t really pleased with our execution of our passing tonight and I think from the word go to the end, we just lacked a bit of spark.”

Deprived of influential midfielder Danny Tiatto and playmaker Marcinho, Frank Farina brought in Stuart McLaren and Massimo Murdocca to fill the gaps in the centre of the park alongside Matt McKay who survived his own injury scare this week to take his place in the side.

The only other change was in defence where Hyuk-Su Seo replaced Ben Griffin at right full-back.

The opening period was a quiet affair but the best early chance fell to Robbie Kruse who latched onto Matt McKay’s through ball in a flash but failed to get power into his shot.

Roar were starting to impose themselves on the game and on 25 minutes McKay was the creator again when his swirling free-kick was well won by Reinaldo and the ball fell at the feet of Sasa Ognenovski whose goal-bound shot was blocked by Cornthwaite.

Just before the break the visitors almost opened the scoring when Liam Reddy’s long goal-kick evaded everyone and was chased down by speedster Michael Zullo.

The youngster homed in on the penalty area but from a tight angle his shot flashed across goal, missing by inches.

Adelaide had rarely threatened but Cassio’s neat one-two with Giraldi almost put the Brazilian in the clear but Kruse tracked back well for Roar and took the ball off the defender’s toe at the crucial moment.

The resulting corner found Robert Cornthwaite unmarked at the far post but with the goal beckoning he swept the ball into the side netting and the scores remained deadlocked at the break.

It was a dull opening to the second period and Roar squandered a great opportunity to take the lead on the hour.

McKay chased down possession in midfield and the loose ball was picked up by Zullo who left Pantelis in his wake as he tore towards goal.

A defence-splitting pass found Reinaldo unmarked but the Brazilian’s powerful drive was straight at United ‘keeper Galekovic who palmed the ball over the bar.

Reinaldo made amends soon after though and put Roar in front with his spectacular finish.

From that point on the Queenslanders proceeded to close off the game, perhaps learning the lessons of last week’s late capitulation against Perth Glory.

In a sterling team performance Captain Craig Moore and midfielder Matt McKay were immense for the visitors, but the plaudits will be reserved for Reinaldo who ended his barren spell in front of goal in true Brazilian style.