Celtic's critical Ange Postecoglou contract error LAST season

Bosnich watched on as Postecoglou wrestled the title back from Rangers at the first time of asking as well as lifting the League Cup in his maiden season.

The 57-year-old guided Celtic to a world record eighth treble in his second season and will now jump ship south of the border to become the new manager of Tottenham Hotspur.

The former ex-Aston Villa, Chelsea and Manchester United and Socceroos shot-stopper insists the Celtic board should have acted 12 months ago and persuaded him to sign a multi-year deal rather than stick with the one-year rolling contract.

READ MORE: Giving Celtic the cold shoulder and Postecoglou punditry sessions - Mark Bosnich Big Interview

Bosnich said: "It was short and sweet with Ange. I'm sure the Celtic fans worldwide will look around and thank Ange for the good times that he brought the club. They probably didn't think it would end so quickly.

"I have to say at the end of last season when he won the double I would not be having Ange on a one-year rolling contract. That was the ideal time for the Celtic board to nail him down on a longer-term deal to safeguard themselves in the eventuality and likelihood that a club like Tottenham Hotspur came in for him.

"From what I am reading and seeing he wanted to go anyway but I don't know all the ins and outs. Celtic would have got a lot more compensation had they had Ange tied down on a four or five-year contract.

"It is very interesting to note that Spurs have offered Ange a two-year deal with another year option. Had Celtic done the same they would be getting a far greater package for his services."

In a former life, Bosnich shared the TV pundit studio with Postecoglou. He readily admits that he knew Postecoglou would return to the beautiful game at some point. However, the former keeper revealed that whilst it is hard to turn down the advances of EPL clubs whenever they come calling he felt that Postecoglou would have stuck around in Glasgow to have one more crack at the Champions League as Celtic manager.

Bosnich said: "I don't think he had anything to lose by remianing at Celtic. I would have liked him to stay and go again in the Champions League. You can't blame him at 57 years of age for wanting to have a crack at the English Premier League which is fair enough. You have to jump on the train at the right time when it comes along. This opportunity might not come along again for Ange.

"I know people talk about when the EPL teams come calling and it is one of the biggest leagues in the world but I still believe that Ange had work to do in Glasgow. He was building towards something with Celtic, especially in Europe. I genuinely thought he'd fancy another crack at the Champions League as he laid great stock in that competition. I thought he'd stay around for another season and try his luck one more time in Europe.

"He is maybe joining Spurs at the right time as they have had an incredibly disappointing season so he can really only help improve their position and standing. By improvement, I mean getting them into the top four in the Premier League and competing for both domestic trophies on offer as Spurs have no distraction of European football this coming season.

"It's getting tougher all the time in the Premier League. You have got clubs like Newcastle United who are ready to challenge again as well as Chelsea. There's also the likes of Brighton and Brentford ticking over quite nicely so it's a hell of a job to take on but it is Ange's nature to go against the grain because he likes a challenge.

"Celtic was a massive challenge for him. He just had to win. There was no safety net of finishing second in Scotland. He was expected to win trophies. That is the expectation at the football club. At Spurs they'd love him to win the Premier League but he is not under intense pressure to do that. He'll need to turn them into a top-four side again and challenge for the FA Cup and League Cup."

The 51 year-old believes that the decision to swap Glasgow for London will not have been taken lightly, especially as Celtic seemed to become very close to his heart.

Bosnich said: "Celtic really got under Ange's skin. I saw that when we had him on the show a couple of times and he spoke about the history of how the club was formed. Ange liked the immigrant backstory. He has always been the outsider in this country and that chimed with him and that's why he enjoyed a wonderful rapport and relationship with the Celtic supporters.

"He found a real affinity with them. I saw that first-hand for myself whenever spoke about Celtic. So make no mistake he will have wrestled with his conscience and it will have been a huge decision for him to leave Celtic for Tottenham."

Bosnich reckons that sometimes in life you need to be careful what you wish for as Postecoglou had a great thing going at Celtic and was in total control of the football side of the operation which certainly won't be the case at Spurs.

Bosnich said: "There is a perception at Spurs is that the manager is not always involved in the player signing process whereas at Celtic it looked like he had total control over who was coming in and out of the club.

"You only have to look at Nuno Espirito Santo who lasted 17 games and Antonio Conte who lasted less than two years with Spurs. You don't know what the future holds when you manage a club like that. I'm not so sure Ange will get such a free rein or the kind of autonomy that he had at Celtic at a club like Tottenham. I don't see him standing for that."

Bosnich jokingly revealed that he has another personal reason for being upset that Postecoglou is no longer the Celtic manager.

He won't be able to slip downstairs in his local boozer and cheer on the men in green and white after Postecoglou reignited his interest in the Scottish game.

Bosnich recalled when Celtic beat Rangers 3-0 at Parkhead last February with a Reo Hatate double and Liel Abada strike in a performance that had 'Angeball' written all over it.

He reckoned the Aussie tapped right into the consciousness of the Celtic faithful when he famously declared: "We’re upholding the values of this football club, not just in terms of winning but the way we play our football. I want them to be proud of us. As I said to the players, we had 60,000 in tonight and I’m sure a lot of them walked in with some problems in their life. For this 95 minutes we made them forget that and feel good and that’s something special.”

Bosnich insists that it was akin to listening to one of the British managerial greats in their pomp and ceremony.

He said: "I'm gutted Ange is leaving Celtic because he single-handedly rekindled my interest in Scottish football. I became a massive Celtic supporter on the back of him being in Glasgow. The pub I visit which shows the football has a Manchester United supporters club upstairs and a Celtic supporters club downstairs. I was always downstairs watching the Celtic games.

"I remember the 3-0 game against Rangers back in February 2022 when Celtic absolutely battered their rivals at Celtic Park. That performance gave me goosebumps. It was so great to see Celtic win by playing in that aggressive attacking manner and free-flowing style knowing an Aussie like Ange was coaching them.

"The words he spoke after the game as well will live long in the memory as it was akin to hearing the likes of Jock Stein, Matt Busby and Bill Shankly in their prime."

READ MORE: Celtic legend Jock Stein remembered: Three Kings filmmaker Jonny Owen on the great man's legacy

Whilst Celtic's loss is undoubtedly Spurs gain, Bosnich predicts a rosy future for the men from Glasgow's east end as he expects there to be an orderly queue of top suitors pitching for one of the better jobs in football and to follow in Postecoglou's footsteps.

Bosnich believes whoever comes next is inheriting a fantastic situation with the added bonus of knowing that Champions League football awaits.

Bosnich said: "As a football manager Ange is a special man. Celtic's loss is definitely Tottenham Hotspur's gain. The next question is who is going to replace him at Celtic? He will be a very hard act to follow.

"Celtic are in a wonderful bargaining position now as they can offer any manager coming in Champions League group stage football and a squad of players who are ready to advance to the next level in their careers.

"Ange is responsible for providing all of that with the success he had had at the club in the past two years. He has made Celtic a viable and attractive proposition for lots of managers.  I have absolutely no doubt in my mind that there will be no shortage of top calibre managerial candidates throwing their hat into the ring for the job after seeing what Ange achieved with Celtic."