Ange Postecoglou has earned high praise from Pep Guardiola, is one of the "top 10 coaches anywhere in the world" and will prove "no second choice".
Those are the words of Tokyo-based football author Scott McIntyre, who adds that the 55-year-old Australian is a "serial winner and tactical innovator".
"Celtic supporters should be absolutely thrilled to grab a guy of his pedigree," said McIntyre on BBC Radio Scotland when asked about the man the club appointed after the long pursuit of Eddie Howe collapsed.
But the former Yokohama F Marinos boss represents "a huge risk", according to Pat Bonner.
"He's very much second choice," said the former Celtic goalkeeper. "I'm absolutely flabbergasted that they are going for someone with no European experience."
And Natasha Miekle, from the Celtic State Of Mind podcast, added: "Every result that goes wrong, every point that is dropped, will be scrutinised through the lens of 'what could Eddie Howe have done?'"
So what can Celtic expect from Postecoglou, who has managed his country and won titles at home and abroad?
Attacking style forged at 'Roarcelona'
"Just because people may not have heard of him does not diminish his record," said McIntyre, who writes for the Asian Game.
"With all due respect, all Eddie Howe has done is win one Championship title in England. Here we're talking about a coach who won back-to-back A-League titles a decade ago, including a 36-match undefeated stint - the longest in any sport in Australia.
"He went on to lead Australia with impressive performances against very strong opposition in the 2014 World Cup. He won the Continental Championship and the Asian Cup. He then led the team to qualification for Russia 2018.
"He came to Japan and, in his second year, won the J-League, which is one of the top 10 leagues in the world."
After a four-cap playing career cut short by a knee injury at age 27, Postecoglou cut his teeth in coaching at South Melbourne, winning successive titles in the A-League's pre-cursor, the National Soccer League.
Seven years in charge of Australia's youth teams and a short stint managing Panachaiki in Greece's third tier preceded his appointment in 2009 at Brisbane Roar, which proved a launchpad for his possession-based, attacking philosophy.
Postecoglou's side were dubbed 'Roarcelona' - a nod to Pep Guardiola's Barca - as their style revolutionised the domestic game and brought silverware.
The Roar team that had finished second bottom were transformed into champions in his two full campaigns.
"He is an absolute adherent of attacking football at all costs," added McIntyre. "With all of his teams, the wingers are inverted, the midfield is pushed up. It is a game based on possession and complete dominance.
"Prior to the pandemic, Manchester City came out to play Marinos and, after the game, Guardiola came up to him privately and said: 'You play the kind of football I dream of playing.'"
Experience of rebuild project
After a year with Melbourne Victory, Postecoglou ascended to the Australia job in 2013. He took over an ageing squad but was attracted by the chance to implement "generational change".
He is clearly a man who relishes a project, which chimes with the huge turnover required at Celtic.
Blooding fresh talent and dismantling the Socceroos' defensive approach, there were signs of progress even in a 2014 World Cup campaign in which Australia finished bottom of a group containing Netherlands, Chile and Spain.
A year later came a milestone triumph as a 2-1 extra-time victory over South Korea sealed the Asian Cup and Australia's first major trophy.
But, by 2017, he had quit, stepping down a week after qualification was secured for the country's fourth consecutive World Cup. With Postecologou at the helm, Australia had risen from 102nd to 43rd in the world rankings.
'He has earned the opportunity'
Postecoglou was soon embarking on a fresh challenge in Yokohama, at a club owned by the City Group.
His side finished 12th in his debut season before he led them to glory in 2019, the club's first title in 15 years. A mid-table finish followed and Marinos are currently third - 21 points off top spot with five games in hand. They lost in the cup to fourth-tier Honda in the Australian's last game in charge.
Those fluctuating fortunes and lack of pressure to win every week have prompted doubts over his suitability for the task at Celtic. But former Australia and Rangers defender Craig Moore has backed Postecoglou to thrive.
"Ange would go in with no fear," Moore wrote on social media. "He would also experience something he has never before in Glasgow. Pressure is daily and you're only ever one game away from a disaster.
"Celtic were a mess this season and I have no doubt he would improve them significantly. He has earned the opportunity."
Postecoglou's teams are rarely dull to watch, with Australian sports writer Ray Gatt saying: "He's a very good coach, with a proven record. Can he handle the demands of immediate success with Celtic? I've got my doubts but wouldn't write him off.
"He is the type of coach who needs time to imbed his philosophy - his teams are attack-minded but can be defensively fragile."
Following a first season without silverware since 2010, frustration over missing out on Howe and with Champions League qualifiers in July, Celtic need their new man to "hit the ground running", says podcaster Miekle.
"Postecoglou might need patience to adapt and to rebuild the squad," she added. "That's not something you readily get at a club like Celtic."