Aaron Mooy's fine debut campaign in the cinch Premiership as caught a few onlookers off-guard – but his manager isn’t one of them.

A few eyebrows were raised when the former Huddersfield Town midfielder signed a two-year deal at Parkhead in the summer, given he hadn’t played a game in months after a stint playing in China drew to a close. He didn’t seem like a neat fit from a tactical perspective either, with some fans concerned that the 31-year-old would struggle to keep up with the high-intensity playing style instituted by Ange Postecoglou.

Fast-forward six months and those fears are looking very silly indeed. Mooy took a little while to get up to speed during the first half of the campaign as he gained match fitness and has been one of his team’s – and the league’s – stand-out players since the Premiership resumed after the World Cup.

The playmaker was once again at the heart of another Celtic victory on Sunday, getting on the scoresheet with a sublime chip in the 4-1 win at McDiarmid Park, as supporters and pundits alike hailed the Australian’s impact on proceedings.

“He is just a quality footballer,” Postecoglou said. “I am not the least surprised by him. I kind of know what is in there and there is a lot more to come. His influence is growing.

“On this pitch, where even good players were struggling, every time he got the ball he was so sure-footed and he kept the ball.

“His balance is unbelievable. He is really strong in terms of his core strength. On days like Sunday you give him the ball and not only will he keep it he will take the right option.

“I thought we would get a lot of joy out wide against St Johnstone with the nature of the pitch. We had everything we needed to combine through central areas in Kyogo [Furuhashi], Aaron and Reo [Hatate] and the two wingers fed off that.”

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A delicate dink from Jota unlocked the Saints defence to send Mooy scarpering through on goal to make it 3-1 on Sunday and the 23-year-old Portuguese admits that Celtic had to vary their attack a little to break down the stubborn resistance that met them.

“There are different situations and you just need to acknowledge what’s the best decision on the pitch,” the winger told Celtic TV. “Sometimes you need to do different stuff to break through their defence, and we just tried to do that.

“That’s something we try to work on every day. We don’t think long-term, we think in the present and we just want to be better.

“We know there’s still plenty of room to develop and we can’t wait for the future to be better and just to being the results to our fans.”