What do Matt O'Riley, Benjamin Siegrist, Harry Kewell and Alexandro Bernabei have in common?

No, it's not the start of a bad dad Celtic joke. On the contrary. The answer is simple: Ange Postecoglou and his seemingly mesmerising telephone calls.

All of the above have been called by the manager to see if they wanted to join him at Celtic.

Whatever Jedi mind-trick Posteoglou has played on each and every one of them it turns out that they are indeed the droids he was looking for.

The 56-year-old clearly possesses a special kind of silver tongue which he has used to fantastic effect so far to persuade others to join him in his attempts to make Celtic a footballing force once again.

That said, Postecoglou has said before he believes Celtic as a club sells itself. Ultimately, it should. Yet it doesn't always hold appeal for players not of these shores and those that maybe don't know their history.

Postecoglou has still been able to coax the likes of Kyogo Furuhashi, Daizen Maeda, Reo Hatate, Yosuke Ideguchi and, now, Alexandro Bernabei to travel thousands of miles across the galaxy and pitch up in Glasgow's east end. And let's not forget Harry Kewell, who joined as a coach recently too.

That is no mean feat. Take Kewell and Bernabei as a case in point. What made them join Celtic? Two words: Ange Postecoglou.

GET OUR FREE CELTIC NEWSLETTER SENT TO YOUR INBOX EVERY DAY

Kewell even ditched the chance of another managerial job to hitch his star to Postecoglou's wagon.

"Funnily enough, I was actually in for another interview for another job and I thought it went really well," the former Leeds United and Liverpool player said. "I was looking forward to a callback but, in between that time, I had a call off the manager. The way he spoke to me and the way he presented the job, I said yes straight away.

"I didn’t even worry about the next part because I felt it was an opportunity for me to learn from not only a great manager, not only an Australian manager but a great manager that has started to do his work in Europe and get his ideas across about what he wants.

"He’s very forthright with what he wants out of his players, and it’s very similar to what I like. The way he spoke to me about football and what he wants from me, I said virtually straight away that yes, I would come."

It was a similar story with Bernabei. He said: "The manager phoned me and he said to me that he believed in my quality. He said also that I can adapt to the team quickly."

Those pesky Postecoglou phone calls. What's he like?

Last season there was a reawakening at Celtic. The whole of Scottish football felt it. If all goes to plan it will be Europe's turn to feel it next.

Whisper it quietly but Postecoglou is fast assuming Yoda-like status at Parkhead.

He is a wise man who, in the space of 10 short months, trained his Celtic team to become Scottish Premiership title winners again.

It's fair to say that the managerial force is strong in this one.

This piece is an extract from today’s Celtic Digest newsletter, which is emailed out at 4pm every weekday with a round-up of the day's top stories and exclusive analysis from The Celtic Way team.

To receive our full, free newsletter including this analysis straight to your email inbox, click here and tick the box for The Celtic Digest