One disappointing home loss to a more than useful Perth Glory does not make Melbourne City a poor side.

The truth, as is so often the case, lies somewhere in between, particularly with a team and a club that is in a state of flux.

City has brought in more than half a squad of new faces this season, the most noteworthy being Tim Cahill.

The Socceroo legend has brought them undreamt-of publicity, has given the A-League a massive boost and announced himself to the Australian football public in the most extraordinary way imaginable last Saturday with that amazing goal which put City on the way to a 4-1 win over Victory.

But Cahill is rising 37 and he can't be expected to produce miracles every time he steps on a football pitch – as was obvious on a cold and wet Friday night.

His contribution was muted, although he did play a key role in City's second equaliser, providing the final pass to Fernando Brandan before the Argentine slotted home to restore parity with the West Australians.

It appeared that parity would stand until five minutes from time when Perth striker Andy Keogh was gifted the winner, the final goal of his hat trick, thanks to a horrific-mix up at the back between full-back Josh Rose and goalkeeper Dean Bouzanis.

Despite the high-tempo start that City have got off to (with two wins before Friday night's loss) the blend of new faces was always going to take time to gell properly, particularly given the fluid and attacking style that John van't Schip is trying to introduce.

City like to get on the front foot and impose themselves on their opposition, but at times they leave themselves light at the back as they try to dominate proceedings at the other end of the pitch.

That was the case on several occasions on Friday night when Perth were able to play through City's midfield press and counter attack to great effect.

Although two of their goals came from set pieces they could have had a couple more on the break when Keogh was denied by a fine Bouzanis save and Nebojsa Marinkovic failed to take advantage of the time and space he was afforded.

To characterise this win as a smash and grab by the visitors would be underselling the performance of Kenny Lowe's team.

The Glory scored twice from set pieces – the first a well-orchestrated move straight off the training ground – and, as mentioned above, had a number of other chances to increase their lead.

Rostyn Griffiths provided power, strength and leadership in the centre of the park and to suggest that they were anything other than good value for their win would be wrong.

For City this is all part of a learning curve. The club would have hoped for a bigger crowd given this was Cahill's home debut on the back of such an impressive start to the campaign, but there were mitigating circumstances on this occasion, the unseasonably wet and cold weather deterring all but the hardiest.

John van't Schip's team are good at getting themselves up for the big occasion, as they did last week, but they have to learn to play with the same fervour and intensity in every game if they are to capitalise on their undoubted talent.

"I think it [the intensity] was lacking. As I said, if you want to play in a certain way, the intention that you have, it's not that easy, everybody has to be connected and be at a high level and we have to do the things we are working on and I think tonight we tried but the performance was not there," van't Schip said.

"We lost the ball too early and then you make the opponent strong and dangerous and we didn't really get into our game. Even though we came back two times ... it was just too average and I think it shows that we're in a process of trying to do something, trying to get to a certain level but today we didn't reach that level and we're back on earth after the game we played against Victory.

"We took a step back and it cost us the game. We have to react and have a good look at what we did this evening and move on."

He agreed that it looked as though it looked as though the team might have been suffering a derby hangover, but said that the reasons for the defeat were straightforward.

"We just didn't keep the ball long enough that we could really get into positions to start playing the way that we want to play ... I think we lost the ball too early, we maybe played the ball long too early and I think we were just too sloppy."

There is little rest, as City must regroup quickly now for their FFA Cup semi-final against Victory on Tuesday night.

Meanwhile, it might have been a night to forget for the City faithful but 17-year-old midfielder Daniel Arzani will not forget the evening as he made his A-League debut for the club, replacing Anthony Caceres in the 78th-minute of what was City's first home defeat in eight meetings with the West Australians.