Ange Postecoglou is adamant his back-to-back Premiership champions will return even stronger for next season.

Standing still is not an option for the Celtic manager after his team clinched the league title 13 points clear of Rangers. A 2-0 victory over Hearts at Tynecastle on Sunday finally put the ribbons on the trophy, the Parkhead club’s 11th league triumph in the past 12 seasons.

Postecoglou and his players returned to Celtic Park to savour their success with a huge crowd, and can still break the top-flight’s record points tally over the remaining four fixtures. The 57-year-old coach conceded that improving upon this campaign’s results – Celtic have lost just one domestic match all season – will be difficult, but when casting an eye over his young squad he believes there is still plenty of room for growth in many of them.

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And he also admits he is determined to ensure they do not allow their rivals to creep up in the rear view mirror by not building on this term’s achievements.

“You can always improve,” said Postecoglou. “That’s my role. A lot of these guys are still young in terms of their football careers. I think there is improvement in us as a group. The experiences we’ve had this year, whether that is in Europe or domestically, make us stronger.

“It will be our task to make sure. It’s what I said at the end of last year: if we stand still, if we come out next year as the same team we were this year there is always the chance that somebody can overtake you.

“We can’t let that happen. We have to push on and make sure we become a better team.

“Results-wise that will be awfully difficult because it has just been an incredible standard, but in terms of the football there is always room for improvement.”