Celtic boss Ange Postecoglou is currently plotting potential moves in the upcoming January transfer market, with the 57-year-old likely seeking to find yet another hidden gem who can go on to strengthen his relentless, title-chasing outfit.

The experienced coach will do well to replicate the success of the winter window earlier this year, however, having notably brought in the likes of Daizen Maeda, Reo Hatate and Matt O'Riley to add further quality to his ranks.

The introduction of the latter man, in particular, has proven something of a masterstroke as far as the Parkhead outfit are concerned, with the former MK Dons man having flourished during his time in Scotland to date.

Since joining for what can be considered a "bargain" fee - in the words of journalist Sean McGinlay - of just £1.5m back in January, the 21-year-old has swiftly cemented his place as a leading figure in Postecoglou's side, racking up 13 goal involvements in 42 games from his midfield berth.

The classy playmaker has notably caught the attention as a result of his form so far this season, chipping in with seven assists in just 15 Scottish Premiership outings, having also been something of a shining light in the Glasgow side's disappointing Champions League campaign.

Journalist Guillem Balague lauded the Denmark U21 international's display during the encouraging defeat to Real Madrid at Celtic Park back in September, stating that the youngster "did not look out of place at all against Madrid and will reach bigger highs for sure."

An elegant and silky creative asset, the London-born "machine" - as dubbed by former boss Russell Martin - has also showcased another facet to his game of late after taking on a deeper role in the absence of skipper, Callum McGregor, having been praised for putting in an "enormous shift" in recent weeks, in the words of his manager.

Such a versatile talent will, however, likely have Postecoglou sweating over his ability to keep hold of the £12k-per-week gem for the long-term, with the 6 foot 2 ace having seemingly been courting attention from clubs across Europe in the summer, with Manchester United one of those said to be keeping tabs on his progress.

The suggestion at the time was that were the Bhoys to cash in they could rake in a fee of around £15m - £20m, although the latest claim is that valuation could have increased even further, with journalist Sean Martin tipping him to eclipse the club record sale of Kieran Tierney to Arsenal in 2019 for a fee of £25m.

Speaking on the Celtic Way podcast, Martin stated: “We’ve said already this summer that both of us believe that Matt O’Riley when he does go, if he continues this trajectory, he will break Kieran Tierney’s Scottish transfer record.

“He ticks every box. Literally every box. The only thing is that he’s not quite there yet because he doesn’t score enough.  That is actually the only thing I would see as missing in his game just now.

“But he’s 21 and that will come. I think that there’s enough about his game that you know that that will come. He will add some more goals. If it’s an English Premier League add on a tax of a few million.

“I just don’t see a world, barring serious injury, where he does not blow that Kieran Tierney Scottish transfer record out the water.”

While the Scottish champions will be desperate to keep hold of O'Riley for now, it seemingly represents just what an astute investment his capture was that he could now be worth over £20m more than what he was signed for, with Postecoglou having truly struck gold.