If that inconsistency and a spot on the fringes of the top six suggests a side talented but not quite title-challengers, that assessment was reflected by what transpired in North Queensland.
After surviving an early onslaught, the Phoenix appeared quite capable of walking away with three points, especially after the red-hot Roy Krishna struck on the stroke of halftime to emphasise his status as his side's most dangerous player.
But such a result would have likely produced a few wry smiles among the visitors, considering the regularity with which their defence was pried open. After surprising by leaving the returning Ben Sigmund on the bench and starting Matthew Ridenton at left back, Merrick will be unlikely to repeat such a selection next week against Sydney FC.
Brisbane found space behind Ridenton and Louis Fenton with ease, and while Andrew Durante and Manny Muscat at times excelled with their desperation defending, the degree of that desperation soon became quite concerning.
In fact, Merrick would have been worried as early as the drinks break midway through the first half, necessitated by soaring temperatures in Cairns. The Phoenix appeared ready for a drink after spending the opening quarter in a state of duress, with the home side seizing control and left frustrated only by several sliding interventions and just as many timely interceptions.
While the Phoenix began to enjoy more of the ball after the break, Brisbane were once again finding holes in the final third, bossing their opponents but struggling to manufacture many clear sights of goal.
And the Roar were made to pay for their profligacy right before the halftime break, when Krishna's well-taken goal gave Wellington a scarcely-deserved lead.
The Phoenix started the second spell as if their advantage was entirely just, with Roly Bonevacia and Alex Rodriguez both spurning good chances. Wellington were continuing to live dangerously at the back and, although Glen Moss was yet to make any saves of significance, the equaliser was always threatening to arrive.
While they had perhaps been guilty of trying to walk in the ball, when the goal did come for Brisbane it was in rapid fashion, with Steven Lustica finishing off a fine counter-attack moments after Michael McGlinchey had been denied at the other end.
Suddenly the Phoenix were in danger of ending up empty-handed, with the match quickly becoming an individual battle between Moss and Jamie Maclaren. And after the goalkeeper's outstretched leg stopped the Brisbane striker for a fourth time in quick succession, Maclaren eventually emerged triumphant with the winner four minutes from time.
Brisbane Roar 2 (S. Lustica 70, J. Maclaren 86)
Wellington Phoenix 1 (R. Krishna 44)
Halftime: 0-1
