Celtic midfielder Matt O'Riley is reportedly attracting interest from clubs across Europe, following his impressive recent form at Parkhead.

What's the word?

According to ESPN, the 21-year-old is earning admiring glances from the likes of Manchester United, Liverpool and Arsenal - as well as Borussia Dortmund - with a 'late move' for the Denmark under-21 international potentially in the offing before the end of the transfer window.

The report suggests that the playmaker - who only arrived in Glasgow on a £1.5m deal from MK Dons in January - could potentially be allowed to depart if a fee of around £15m-£20m is received, albeit with the Premiership champions having no real interest in sanctioning a sale.

The report adds that if a bid is made, it would most likely come from either Newcastle United or Brendan Rodgers' Leicester City, while O'Riley has also been scouted by both Wolfsburg and Lille of late.

Postecoglou must avoid disaster

While it is testament to the youngster's form that he is already the subject of such vast interest from some of the continent's leading clubs, those at Parkhead will likely be concerned about losing a player who has already become a key figure under Ange Postecoglou.

The title-winning coach simply must resist any approaches for the 6 foot 2 sensation over the next few days, with Celtic unable to afford to lose another midfield talent, having seen the long-serving Tom Rogic depart at the end of last season.

O'Riley - who has been tipped to become the heir to the Australian in Postecoglou's side - made an instant transition to life in the Premiership after joining in the winter, scoring four goals and providing three assists in just 16 league games last term.

Dubbed a "pressing machine" by his former MK Dons boss Russell Martin, the former Fulham youth product has also started brightly in the early weeks of the new campaign, laying on one assist so far after starting all four league games for Celtic.

Having made the jump from life in English League One to the more pressurised environment at Parkhead, the £2.07m-rated ace has already enjoyed something of a meteoric rise of late, with another step up to a club in Europe's top five leagues no doubt on the horizon.

For now, however, Postecoglou and co must hold firm and keep O'Riley at the club, particularly with a crucial Champions League group stage voyage set to get underway at home to Real Madrid next month. Cashing in on him before them could be disastrous, as finding an attainable, good-value replacement of equal quality before the transfer window shuts would be nigh-on impossible.