Harry Kewell's energy can help Celtic go up a level - Postecoglou
Kewell has joined his compatriot as a first team coach
Ange Postecoglou believes Harry Kewell brings an "energy and enthusiasm" that can help Celtic step up a level next season.
The former Oldham and Crawley manager was recruited to his fellow Australian's backroom staff ahead of the upcoming season.
In Postecoglou's first season at Parkhead he won the title and League Cup and he believes Kewell's introduction can help with the desired improvement in a season which sees Celtic go straight into the Champions League.
Speaking to Sky Sports Scotland at Celtic's training base in Austria, Postecoglou said: "I am always very conscious of making sure that every year we bring a freshness to everything we do, particularly with the players.
"We had a successful season last year but we know we have to go up a level this year.
"I think sometimes if players come in and see no change I don't think it sends the right message.
"Harry has had a crack at trying to be a manager and he want to carve out a career for himself and he brings some real energy and enthusiasm for us."
Christopher Jullien's future at the club was also addressed by Postecoglou.
It was reported that the French defender was heading for a season-long loan at Schalke before the proposed deal collapsed.
Jullien played for most of Wednesday night's friendly against Wiener Viktoria and also scored in the 7-0 win.
Postecoglou said: "Everyone's future is the same. Everyone's future is unknown. None of us have any certainty about what we do.
"With Christopher and the other lads, they are training with us and while they are with us I treat them as one of our players, and if that changes in the future it changes.
"The mood between me and him is the same as between me and Callum (McGregor, captain), there is no difference. He is a player at Celtic, I'm the manager and that doesn't change with all the players.
"We had a similar situation last year with Ryan Christie, Odsonne Edouard, Kristoffer Ajer and I think if you speak to them, I didn't treat them any differently.
"In terms of what we are trying to do and what we are planning for, we are still looking to bring in two or three players, there are still a couple of areas we need to strengthen in and we will do that."
On defender Josip Juranovic, linked with Atletico Madrid recently, Postecoglou said: "He is part of the furniture here. He is training well.
"As I said, everyone's future is uncertain.
"The key to it all is that whatever happens in the future is really determined by what happens today.
"With Josip and the other boys who had fantastic seasons last year, the key now is to improve this year and if they improve this year, all those things take care of themselves."
Founded in 1888, Willie Maley was Celtic's first manager and one of the most successful managers in Scottish football history. He managed the club from 1897 to 1940, winning thirty major trophies (16 league championships and 14 Scottish Cups).
Jimmy McStay (circled) managed Celtic between 1940 and 1945. However, this clashed with the suspension of the League and Scottish Cup during wartime, meaning he never had the opportunity to manage the club in official competitions.
All-time leading goalscorer in top-flight British football Jimmy McGrory managed Celtic from 1945 to 1965. He won one First Division trophy, two Scottish League Cups, two Scottish Cups, four Glasgow Cups, one Coronation Cup, one Saint Mungo Cup and four Glasgow Charity Cups.
Jock Stein managed Celtic from 1965 to 1978 and guided Celtic to nine successive Scottish League championships between 1966 and 1974. He also won one European Cup, eight Scottish Cups, six Scottish League Cups, five Glasgow Cups and one Drybrough Cup.
Billy McNeil managed Celtic from 1978 to 1983. McNeil won three Scottish League titles, one Scottish Cup, one Scottish League Cup and one Glasgow Cup.
McNeil returned from 1987 to 1991 where he won one Scottish League title and two Scottish Cups.
David Hay managed Celtic from 1983 to 1987 and won one Scottish League title and one Scottish Cup.
Liam Brady managed Celtic from 1991 to 1993 but failed to win any trophies.
Lou Macari managed Celtic from 1993 to 1994 but he failed to win any trophies.
Tommy Burns managed Celtic from 1994 to 1997 and he won one Scottish Cup.
Wim Jansen managed Celtic from 1997 to 1998 and won One Scottish Premier Division Title and One Scottish League Cup.
Jozef Venglos managed Celtic from 1998 to 1999 but did not win any trophies
John Barnes managed Celtic from 1999 to 2000 but did not win any trophies.
Kenny Dalglish managed Celtic in 2000 and won one Scottish League Cup
Martin O'Neil managed Celtic from 2000 to 20005 and won three Scottish Premier Leagues, three Scottish Cups and one Scottish League Cup.
Gordon Strachan managed Celtic from 2005 to 2009 and won three consecutive Scottish Premier League Titles, one Scottish Cup and two Scottish League Cups.
Tony Mowbray managed Celtic from 2009 to 2010 but failed to win any trophies.
Neil Lennon managed Celtic from 2010 to 2014 and he won three Scottish Premier League titles and two Scottish Cups.
Lennon returned from 2019 to 2021, where he won two more League titles, two Scottish Cups and one Scottish League Cup.
Ronny Delia managed from 2014 to 2016 where he won two Scottish Premierships and one Scottish League Cup.
Brendan Rodgers managed Celtic from 2016 to 2019 where he won two Scottish Premierships, two Scottish Cups and three Scottish League Cups.
Ange Postecoglou took over as Celtic manager in 2021 and has won a Scottish League Cup.