Martin O'Neill was keen to stress that his Celtic side is still "well short" right now, but that might be an ominous sign for the rest of the Premiership.

Following Wednesday's 1-0 win over St Johnstone, the champions remain perfect with six wins from six, even while having not necessarily started motoring as yet.

The men in green and white certainly made hard work of it in Perth, with a rotated outfit unsurprisingly taking a while to click into gear in that narrow victory.

And yet, if there was one key reason to be positive, it was the performance of the new signings, with Haissem Hassan again among those to make the difference against the Saints.

Handful Hassan shows what he's all about in St Johnstone win

With Yang Hyun-jun now on international duty, and with substitute Camilo Duran afforded a rest, it felt like a big night for the two men on the flanks.

In the case of Sebastian Tounekti, the Tunisian produced the type of performance that has become far too familiar since his arrival last year, with all the endeavour ultimately proving futile amid the lack of end product.

As for Hassan, well, the 1-0 win proved far more fruitful in that sense, the fleet-footed Egyptian causing all sorts of problems down the right flank.

Yes, the 24-year-old looks like someone who might frustrate if the flicks and tricks amount to nothing, but there were more than enough moments of magic in this latest outing.

A delightful, delicate dink over the top almost found Mika Baur in the first half, while Hassan also worked the ball nicely onto his left foot to flash an effort on goal at the near post.

It feels like he could be a little more direct at times, as when he is, the former Real Oviedo man looks so deadly, having been controversially denied a goal of his own as the ball was deemed to have gone out of play.

Thankfully, his first goal involvement for the club did come after the break, the left-footer picking out Baur with a perfect pull-back following a fine initial flick in the build-up.

It's early days, but the £6m man already looks like an astute signing, and he isn't alone in that regard.

Why Postecoglou would have loved Celtic's stellar signing

O'Neill has helped to turn this team into a formidable, winning outfit in the Premiership, but the football on show is still a far cry from the glorious days of Ange Postecoglou.

The Glasgow giants were almost playing a different sport at times during the Aussie's two-year spell, so fluid, so relentless all across the park.

That brand of football hasn't been seen in a wee while, it must be said, although there are members of this current crop who look like they'd be perfectly suited to a Postecoglou-style approach.

Hassan might well be one of them, as does Duran, although the biggest positive following Wednesday in that sense was matchwinner Baur, the German putting in his "best game in a Celtic jersey", in the view of Scott Brown on Sky Sports.

While fellow midfielder Oliver Sorensen proved rather anonymous ahead of him, Baur again helped to pull the strings alongside Callum McGregor, the 22-year-old simply just a glorious footballer to watch.

Signed for a total fee pushing £7m from Paderborn, the diminutive playmaker has been an instant hit at Parkhead, ever since his flick on debut away at Tannadice.

He may not be the swashbuckling, rampaging number eight that was needed to directly replace Arne Engels, but it's hard not to be impressed by his technical quality and ball-playing prowess.

Those are traits which certainly would have seen him slot in nicely during the Postecoglou days, with his clear likeness to Reo Hatate backing up that point even further.

Indeed, the manner in which he found himself free inside the area to slot home on Wednesday night certainly was Hatate-esque, mirroring the Japanese genius as someone who has so many strings to his bow in the centre of the park.

Not only did Baur score against Simo Valakari's men, but he also enjoyed a 90% pass accuracy rate, completed three out of his six crosses, provided one key pass and won five of his seven duels, having racked up 72 touches in total.

In certain games, particularly in Europe, this McGregor-Baur axis may come undone, but in the Premiership the pair can offer so much control, dictating games for fun if they wish.

While Wednesday night wasn't the perfect display by any stretch from the league leaders, the impact of Hassan, and more so Baur, has suggested that the club might have turned a corner in terms of recruitment.

Could the days of Postecoglou be on the horizon again?