Scottish Premiership champions Celtic are currently continuing their rampant title charge under Ange Postecoglou, with one key component in their recent relentless form having been the displays of summer arrival Aaron Mooy.

After an initial low-key start to life at Parkhead following his free transfer - having notably been hooked at half-time in the defeat to St Mirren in September - the 32-year-old has been reborn following his involvement at the World Cup with Australia.

An "immense" presence for his country in Qatar according to journalist Josh Bunting, the experienced midfielder has seen been in "outstanding" form for the Old Firm outfit according to his manager, with 12 goal involvements to his name in all competitions so far this season.

That includes a haul of four goal contributions in his last four Premiership outings, having notably produced a "filthy" finish (as per journalist John McGinley) during the most recent triumph away to St Johnstone on Sunday.

Now "one of Celtic's best", as per writer Sacha Pisani, the addition of the former Huddersfield Town man is already proving an astute piece of business, with Postecoglou having teased that a long-term deal could be in the offing for the £23k-per-week maestro in the near future.

However, perhaps one source of frustration for the Glasgow giants will be that the 57-cap gem could have arrived at Paradise a year earlier, with 90min reporting in the summer of 2021 that Postecoglou had been pushing to sign his compatriot from Chinese outfit Shanghai Port.

While the report did suggest that any deal would likely have to require a fee of around £4m - a potential sticking point for the Bhoys - Mooy's impact of late would seem to highlight that such an outlay would well have been worth it.

It will also be of real annoyance as to who the club opted to sign instead at the time, with Republic of Ireland international James McCarthy having joined on a four-year deal after leaving Crystal Palace at the end of his contract.

As the 90min report outlined, Postecoglou had seemingly been keen on bringing in Mooy, although the Celtic hierarchy had been earmarking a move for McCarthy even before an appointment had been made - albeit with the new boss still likely to have the final say.

The decision to plump for the latter has no doubt backfired, such have been his woes of late. The 32-year-old has gone on to make just 27 appearances in all competitions to date for Celtic, with only six of those coming from the start.

A player who has simply "disappointed" over the last 18 months, according to Frank McAvennie, the former Everton man has endured a particularly dismal, injury-hit 2022/23 campaign so far, making only five appearances across all fronts.

It would appear that Celtic are now regretting their "strange" decision, in the words of former Scotland defender Alan Hutton, to hand McCarthy such a lengthy contract at the time of his arrival, amid reports ahead of the January transfer window that they were already keen to offload him.

As such, while hindsight is a wonderful thing in football, it does appear to have been something of a howler not to have secured an earlier move for Mooy, rather than snapping up the struggling Irishman in 2021.