It was a humiliating loss for the Roar and leaves coach Rado Vidosic with some serious questions to answer about his side's lack of intensity and fluency.

This win lifts Heart off the bottom of the table and - at least until Saturday night - above cross-town rival Melbourne Victory, but sends the once impregnable Roar to the basement. Brisbane has only one win in its first six matches and has lost its last three in a row, scoring just once - Friday night's late consolation from Henrique - en route.

Heart had gone to the interval a goal to the good before a devastating spell, orchestrated by Croatian striker Josip Tadic and ably abetted by Richard Garcia, netted it three goals in a 12-minute spell in the second period to put the Heart 4-0 up by the 74th minute and the game in safe keeping.

For a side that struggled to convert its chances in earlier matches, this was a veritable bursting of the dam, with Garcia and centre-back Patrick Gerhardt scoring their first goals for the club, alongside Tadic and substitute David Williams, who were also on the scoresheet.

Garcia was deployed in a more forward role than to date and his workrate, dynamism and intensity galvanised Heart. The former West Ham and Hull man had complained in earlier games that the team was not playing with the pace and fizz required and he seemed determined to set the tone. Tadic also worked hard, closing down Brisbane defenders at every opportunity in a bid to stop the champion outfit playing out from the back. In fact, Brisbane looked lacklustre and hesitant at the back and lacked the fluency that was the hallmark of the title-winning seasons.

Heart coach John Aloisi had shaken things up in his side's midfield in the continued absence of captain Fred and gave Jason Hoffman a chance in the centre of the park, with another tall midfielder in Nick Kalmar used in a wide role.

The host got the breakthrough it deserved on 20 minutes. Hoffman's run down the right took him past two challenges and, although he was dispossessed, the ball broke to Mate Dugandzic. The winger's first-time cross was driven low to the near post and central defender Gerhardt nipped in first to slide the ball home.

The Roar shook itself out of its lethargy for a time after the goal. Thomas Broich became more involved in the attacks as Brisbane finally began to find some cohesion, but it created little. Brisbane looked to have scored an equaliser five minutes before the interval when Mitch Nichols stretched wonderfully to pull the ball back from the byline for Henrique to beat Clint Bolton with a cleverly taken shot. But a linesman flagged that the ball had gone out of play before Nichols' touch - although replays suggested it was still in.

Roar began the second period more enthusiastically as it went in search of a leveller but as it did the game stretched and Tadic's influence became more signifcant. The former Dinamo Zagreb and Bayer Leverkusen striker broke on the right and sold Roar centre back Matt Jurman a dummy before squaring the ball for Garcia, who struck the pass with his left foot.

The Croatian was almost on target himself shortly after and eventually got the reward he deserved for a great night's work in the 71st minute when he converted a penalty awarded for Jurman's clumsy challenge on Garcia. David Williams' cool finish when he ran on to Aziz Behich's through ball three minutes later completed the rout.