Celtic midfielder Callum McGregor admits last term’s success will count for nothing as Ange Postecoglou’s team bid to prove they are no one-season wonders.

The Hoops exceeded expectations in the Australian’s first year as manager as a new-look team delivered a Premiership title and the Premier Sports Cup despite starting the campaign in a state of transition.

Captain McGregor admits the big challenge for his colleagues in the upcoming season will be to prove they have the mindset to become serial winners.

“I’m buzzing to get the season under way,” he told Celtic TV ahead of Sunday’s league opener at home to Aberdeen. “We feel we’re in a good place and everybody’s looking forward to the first game.

“We’re a year on from where we started (under Postecoglou) and that will bring different challenges. We need to handle all the challenges that will be thrown at us and we have to rise to that.

“It’s so important that we draw a line under last season. This will be a new season with new challenges. It’s up to us experienced ones to guide the group through that.

“The players that came in did brilliantly last season and it’s another challenge for them to say ‘can you go again and produce that level and potentially even more in the season coming?’

“I think everybody’s well aware of the challenges that lie ahead. We have to commit to them together as a group and if we do that, we’ll be in a good place.”

McGregor admits he is “super proud” after being asked to unfurl the Premiership title flag ahead of Sunday’s match at Celtic Park.

“When you think about the names that have done it over the years, for the club to ask me to do it is a huge honour, and for my family to watch that,” he said.

“I’m very grateful to get the opportunity to do it.

“It’s always a brilliant day to unfurl the flag at Celtic Park. There’s a real buzz and energy about the place with anticipation of the new season ahead.

“It’s important we get our mindset right for that in the next few days at training, give a good performance and try and get a good result.”

Celtic have been unbeaten through their pre-season campaign and McGregor feels they are in good fettle ahead of the big kick-off.

“Pre-season is a lot about fitness and getting your work in but we’re also trying to build a winning mentality,” he said.

“It’s important that we’ve come through pre-season undefeated and we’ll try and take that mentality into the season.

“There will be a lot of challenges so it’s important that everyone stays together, including the supporters. That will be the foundation for a positive season hopefully.”

McGregor is braced for a stern test against a Dons side who go into their first full season under Jim Goodwin with renewed optimism following an eye-catching summer transfer window.

“Early on in the season, teams have had their pre-season and they’re feeling good about themselves,” said McGregor. “Everybody wants to start in a positive manner and Aberdeen will be the same.

“Jim’s sides are always really organised, really tactically astute. It’ll be a tough game and we have to be ready for it to get a positive result to start the season off.”

Celtic defender Osaze Urhoghide has rejoined KV Oostende on a season-long loan. The 22-year-old has struggled for game time since joining the Hoops from Sheffield Wednesday last summer and he has been allowed to return to the Belgian club at which he spent the second half of last season.